Absorbent article

ABSTRACT

The objective of the present disclosure is to provide an absorbent article having a dry top sheet without any feeling of stickiness in the top sheet, even after high viscosity menstrual blood has been absorbed. The absorbent article of the present disclosure has the following structure. The absorbent article ( 1 ) has a liquid-permeable top sheet ( 2 ), a liquid-impermeable back sheet, and an absorbent body ( 3 ). The absorbent article ( 1 ) is characterized by: having an excretory orifice contact region ( 4 ), first embossed portions ( 5 ), an external peripheral region ( 6 ), and second embossed portions ( 7 ); the first embossed portions ( 5 ) and second embossed portions ( 7 ) being formed by embossing a layer comprising the top sheet ( 2 ) and the absorbent body ( 3 ); and the top sheet ( 2 ) inside the excretory orifice contact region ( 4 ) and the second embossed portions ( 7 ) respectively comprising a prescribed blood lubricating agent.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a National Phase of International Application Number PCT/JP2013/058862 filed Mar. 26, 2013, which claims the priority of Japanese patent Application No. 2012-084321 filed Apr. 2, 2012.

TECHNICAL FIELD

The present disclosure relates to an absorbent article.

BACKGROUND ART

As the basic performance of absorbent articles, such as sanitary napkins and panty liners has continued to improve with technological development over many years, leakage after absorption of excreta, such as menstrual blood has become a less frequent occurrence than in the past, and research is currently ongoing with the aim of achieving even higher performance, including a feel similar to underwear, and smoothness of the top sheet even after absorption of excreta, such as menstrual blood.

Menstrual blood during menstruation, in particular, can also contain components of the endometrium which are highly viscous, and the top sheet preferably remains smooth and stick-free even after absorption of such highly viscous menstrual blood. Highly viscous menstrual blood usually remains on the top sheet in the form of masses, generally leaving the user with a visually unpleasant image, and therefore from this viewpoint as well it is preferred for no highly viscous menstrual blood to remain on the top sheet.

For example, PTL 1 discloses an absorbent article having a polypropylene glycol material-containing lotion composition situated on the inner surface of the top sheet (the clothing side surface), the inner surface of the back sheet (the body side surface), and on the base material between the inner surface of the top sheet and the inner surface of the back sheet.

Also, PTL 2 discloses an absorbent article wherein a polypropylene glycol material-containing lotion composition is applied on the outer surface of the top sheet (body side surface).

CITATION LIST Patent Literature

-   PTL 1 Japanese Unexamined Patent Publication No. 2010-518918 -   PTL 2 Japanese Unexamined Patent Publication No. 2011-510801

SUMMARY OF INVENTION Technical Problem

When menstrual blood is absorbed in an absorbent article, there is often little correlation between the degree of reddening of the top sheet by menstrual blood and the amount of menstrual blood absorbed by the absorbent body. Particularly with absorbent articles in which the top sheet is not easily dyed red by menstrual blood, the wearer often does not realize that the absorbent body has absorbed menstrual blood up to near the limit of its absorption volume and that it is time for replacement.

The absorbent articles described in PTLs 1 and 2 are not designed so that the time for replacement of the absorbent article is visually recognizable. In addition, they are not designed to reduce the risk of leakage when the time for replacement has elapsed.

It is therefore an object of the present disclosure to provide an absorbent article without a sticky feel on the top sheet and with a smooth top sheet, even after highly viscous menstrual blood has been absorbed, and that allows the time for replacement to be visually recognized and reduces the risk of leakage.

Solution to Problems

As a result of diligent research directed toward solving the problems described above, the present inventors have discovered an absorbent article comprising a liquid-permeable top sheet, formed from a nonwoven fabric or woven fabric, a liquid-impermeable back sheet, and an absorbent body between the top sheet and the back sheet, wherein the absorbent article has, in a region overlapping the absorbent body in a thickness direction, an excretory opening contact region that contacts with an excretory opening of a wearer, a first embossed section which is continuously or discontinuously disposed and which surrounds the excretory opening contact region, a fringe region on an outer side of the first embossed section, and a second embossed section disposed in the fringe region, located on an outer side of the excretory opening contact region in a lengthwise direction, the first embossed section and second embossed section are formed by embossing a layer comprising the top sheet and the absorbent body, and the top sheet within the excretory opening contact region and the second embossed section each comprise a blood slipping agent that has a kinematic viscosity of 0.01 to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0 mass % and a weight-average molecular weight of less than 1000.

Advantageous Effects of Invention

The absorbent article of the present disclosure has no sticky feel on the top sheet, while also having a smooth top sheet, even after highly viscous menstrual blood has been absorbed, and it allows the time for replacement to be visually recognized and reduces the risk of leakage.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a sanitary napkin according to an embodiment of the absorbent article of the present disclosure.

FIG. 2 is a front view of a sanitary napkin according to another embodiment of the absorbent article of the present disclosure.

FIG. 3 is an electron micrograph of the skin contact surface of a top sheet in a sanitary napkin wherein the top sheet comprises tri-C2L oil fatty acid glycerides.

FIG. 4 is a pair of photomicrographs of menstrual blood containing and not containing a blood slipping agent.

FIG. 5 is a diagram illustrating a method of measuring surface tension.

DESCRIPTION OF EMBODIMENTS

The absorbent article of the present disclosure will now be explained in detail.

FIG. 1 is a front view of a sanitary napkin according to an embodiment of the absorbent article of the present disclosure. FIG. 1 is as observed from the skin contact side of the top sheet 2. The sanitary napkin 1 shown in FIG. 1 has a liquid-permeable top sheet 2, a liquid-impermeable back sheet (not shown), and an absorbent body 3 between the top sheet 2 and the back sheet. In the sanitary napkin shown in FIG. 1, the top sheet 2 is formed from a nonwoven fabric.

The sanitary napkin 1 shown in FIG. 1 has, in the region overlapping with the absorbent body 3 in the thickness direction of the sanitary napkin 1, an excretory opening contact region 4 that contacts with the excretory opening of a wearer, first embossed section 5 which is discontinuously disposed and which surrounds the excretory opening contact region 4, a fringe region 6 on the outer side from the first embossed section 5, and second embossed section 7 disposed in the fringe region 6, located on the outer side in the lengthwise direction of the excretory opening contact region 4. The first embossed section 5 is composed of first embossed sections 5′, 5″, 5′″ and 5″″, and are each independently disposed surrounding the excretory opening contact region 4.

As used herein, the term “excretory opening contact region” means the region that contacts with the excretory opening (e.g. labia minora) of the wearer, and it is defined by an embossed section (first embossed section) which is continuously or discontinuously disposed. The excretory opening contact region will have a different location depending on the size of the absorbent article, and for an absorbent article without wing sections, for example, the excretory opening contact region is the interior area of the region defined by the embossed section (first embossed section) which is continuously or discontinuously disposed so as to surround the widthwise center section and lengthwise center section of the absorbent article. When the absorbent article has wing sections, for example, the excretory opening contact region is the interior area of the region defined by the embossed section (first embossed section) which is continuously or discontinuously disposed so as to surround the intersection between a line in the lengthwise direction that passes through the widthwise center of the absorbent article, and a line in the widthwise direction that passes through the lengthwise center of both wing sections.

In the sanitary napkin 1 shown in FIG. 1, the first embossed section 5 and the second embossed section 7 are formed by embossing the layer comprising the top sheet 2 and the absorbent body 3.

Also, in the sanitary napkin 1 shown in FIG. 1, the top sheet 2 within the excretory opening contact region 4, and the second embossed section 7, each comprise a prescribed blood slipping agent (not shown).

The function of the absorbent article of the present disclosure will now be explained with reference to FIG. 1.

Highly viscous menstrual blood first reaches the excretory opening contact region 4 of the sanitary napkin 1. Since the top sheet 2 in the excretory opening contact region 4 contains a blood slipping agent, the menstrual blood migrates into the sanitary napkin 1 together with the blood slipping agent, and rapidly migrates into the absorbent body 3.

Thus, the sanitary napkin 1 allows rapid migration of absorbed menstrual blood into the absorbent body 3.

In addition, menstrual blood migrates into the sanitary napkin 1 together with the blood slipping agent, and therefore the excretory opening contact region 4 of the top sheet 2 is not easily reddened with menstrual blood. As a result, although the wearer is not easily left with a visually unpleasant image of coloration when visiting the toilet, it is often difficult to discern that it is time for replacement of the sanitary napkin, based on the condition of the top sheet.

When a large amount of menstrual blood has been absorbed into the absorbent body 3, menstrual blood migrates in the lengthwise direction and the widthwise direction of the absorbent article in the absorbent body 3. When menstrual blood migrating in the lengthwise direction of the absorbent article reaches the second embossed section 7, which are disposed in the fringe region 6 located on the outer side in the lengthwise direction of the excretory opening contact region 4, the second embossed section 7 that contain a blood slipping agent repel the menstrual blood, pushing it back in the direction of the excretory opening contact region 4. Leakage of menstrual blood is therefore minimized.

Also, a portion of the menstrual blood that has reached the second embossed section 7 is taken up by capillary movement into the second embossed section 7, because they have high fiber density. When menstrual blood is taken up into the second embossed section 7, the wearer visually sees from the top sheet 2 side that the second embossed section 7 has become reddened. This allows the wearer to understand that it is time for replacement of the sanitary napkin 1.

In the sanitary napkin 1 shown in FIG. 1, the top sheet 2 within the excretory opening contact region 4 contains a blood slipping agent over the entire planar direction, but according to another embodiment of the absorbent article of the present disclosure, it contains a blood slipping agent only over part of the planar direction of the top sheet within the excretory opening contact region.

In the sanitary napkin 1 shown in FIG. 1, the second embossed section 7 is disposed and curved so as to surround the edges of the excretory opening contact region 4 in the lengthwise direction. By placing the second embossed section in a curved manner so as to surround the edges of the excretory opening contact region in the lengthwise direction, it is possible to efficiently repel menstrual blood, diffusing in the lengthwise direction of the absorbent article, from the edges of the excretory opening contact region in the lengthwise direction and to push it back in the direction of the excretory opening contact region, thereby inhibiting leakage of menstrual blood. The second embossed section may have, for example, roughly U-shaped, roughly V-shaped, roughly Y-shaped, roughly circular arc-shaped or roughly elliptical arc-shaped forms.

In the sanitary napkin 1 shown in FIG. 1, the top sheet 2 has a non-agent-containing region 9, as a region that does not contain a blood slipping agent, between the excretory opening contact region 4 and the second embossed section 7. By having a non-agent-containing region between the excretory opening contact region and the second embossed section, in cases where, for example, the absorbent body includes a super-absorbent polymer to prevent mustiness during wear, it will not as easily inhibit absorption of moisture by the super-absorbent polymer.

In the sanitary napkin 1 shown in FIG. 1, the first embossed section 5 further comprises a blood slipping agent. The following effects are obtained if the first embossed section comprises a blood slipping agent.

It is generally known that when a wearer is lying down during sleep, menstrual blood that has reached the excretory opening contact region of the top sheet often flows out of the excretory opening contact region along the skin contact surface. In the sanitary napkin 1 shown in FIG. 1, however, the first embossed section 5 surrounding the excretory opening contact region 4 comprises a blood slipping agent, and therefore the blood slipping agent in the first embossed section 5 repels menstrual blood attempting to flow out of the excretory opening contact region 4, pushing the menstrual blood back into the excretory opening contact region 4. The menstrual blood that has been pushed back migrates into the sanitary napkin 1 together with the blood slipping agent of the excretory opening contact region 4, and migrates into the absorbent body 3.

According to another embodiment of the absorbent article of the present disclosure, the first embossed section does not comprise a blood modifying agent.

As shown in FIG. 1, the first embossed section surrounding the excretory opening contact region in the absorbent article may be discontinuously disposed in order to avoid resulting in a hard absorbent article.

The sanitary napkin 1 shown in FIG. 1 also further has four third embossed sections 8′, 8″, 8′″ and 8″″ (hereunder also referred to as “third embossed section 8), on the outer sides of the discontinuous sections 10 of the first embossed section 5. The third embossed sections 8′, 8″, 8′″ and 8″″ are disposed on the outer sides of the discontinuous sections 10 of the first embossed section 5.

The third embossed section 8 is formed in the fringe region 6.

In the sanitary napkin 1 shown in FIG. 1, the third embossed section 8 further comprises a blood slipping agent. Thus, menstrual blood attempting to diffuse over the skin contact surface of the top sheet 2 through the discontinuous sections 10 is blocked by the third embossed section 8, and can be repelled into the excretory opening contact region 4.

According to another embodiment of the absorbent article of the present disclosure, the third embossed section does not comprise a blood modifying agent.

In the sanitary napkin 1 shown in FIG. 1, a total of two second embossed sections 7 are disposed in the fringe region 6 located on the outer side of the excretory opening contact region 4 in the lengthwise direction, but according to another embodiment of the absorbent article of the present disclosure, only one second embossed section may be disposed in the fringe region located on the outer side of the excretory opening contact region in the lengthwise direction, situated, for example, toward the rear for wearers more prone to leakage.

FIG. 2 is a front view of a sanitary napkin, according to another embodiment of the absorbent article of the present disclosure. The sanitary napkin 1 shown in FIG. 2 differs from the sanitary napkin 1 shown in FIG. 1 in that the first embossed section 5 is continuously disposed so as to surround the excretory opening contact region 4, and the third embossed section is not present, but it is otherwise identical to the sanitary napkin 1 shown in FIG. 1.

If the first embossed section 5 is continuously disposed so as to surround the excretory opening contact region 4, as shown in FIG. 2, menstrual blood that attempts to diffuse out of the excretory opening contact region 4 along the skin contact surface of the top sheet 2 or through the interior of the top sheet 2, will be blocked by the first embossed section 5, and can either be repelled into the top sheet 2 within the excretory opening contact region 4, or caused to migrate into the absorbent body 3. This function is increased if the first embossed section 5 comprises a blood slipping agent.

Incidentally, when the first embossed section is continuously disposed and surrounds the excretory opening contact region, as shown in FIG. 2, a lower average basis weight of the blood slipping agent in the first embossed section than the basis weight of the blood slipping agent of the top sheet in the excretory opening contact region may be, for example, (I) a lower average basis weight of the blood slipping agent in the first embossed section due to a uniformly lower basis weight of the blood slipping agent in the first embossed section, (II) a lower average basis weight of the blood slipping agent in the first embossed section achieved by the first embossed section containing the blood slipping agent in a discontinuous manner, or (III) a lower average basis weight of the blood slipping agent in the first embossed section achieved by the first embossed section containing the blood slipping agent on the skin contact side.

If the average basis weight of the blood slipping agent in the first embossed section is high, menstrual blood that has reached the excretory opening contact region will not easily exit the excretory opening contact region in the absorbent body, and the absorption volume of the absorbent body may be reduced as a result.

The sanitary napkins 1 shown in FIG. 1 and FIG. 2 both have a liquid-permeable top sheet 2, a liquid-impermeable back sheet and an absorbent body 3 between the top sheet 2 and back sheet, but according to several other embodiments of the absorbent article of the present disclosure, the absorbent article further has a second sheet between the top sheet and the absorbent body.

In the embodiment described above, the first embossed sections is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.

Also, in the embodiment described above, the second embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.

Furthermore, in the embodiment described above, the absorbent article includes third embossed section, and the third embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.

In this absorbent article of the present disclosure, the top sheet within the excretory opening contact region and the second embossed section each comprise the blood slipping agent at a basis weight in the range of preferably between about 1 and about 30 g/m², more preferably between about 2 and about 20 g/m² and more preferably between about 3 and about 10 g/m². If the basis weight is less than about 1 g/m², the force that causes absorbed menstrual blood to remain on the top sheet and the second embossed section to repel menstrual blood and push it back toward the excretory opening contact region will be weakened, tending to result in more leakage, while if the basis weight of the blood slipping agent is greater than about 30 g/m², a greater degree of stickiness will tend to be felt during wear.

The first embossed section and the optional third embossed section may optionally comprise the blood slipping agent in a range of preferably about 1 to about 30 g/m², more preferably about 2 to about 20 g/m² and even more preferably about 3 to about 10 g/m². If the basis weight of the blood slipping agent is less than about 1 g/m², menstrual blood that has reached the first embossed section and the optional third embossed section may not easily be repelled into the excretory opening contact region. If the basis weight of the blood slipping agent is greater than about 30 g/m², stickiness will tend to be felt to a greater degree during wear.

As used herein, the size of the “excretory opening contact region” differs depending on the size of the absorbent article itself, and for example, it may be a length of about 50 to about 180 mm or about 80 to about 120 mm in the lengthwise direction of the absorbent article, and a length of about 10 to about 60 mm or about 20 to about 40 mm in the widthwise direction of the absorbent article.

Since the blood slipping agent has a kinematic viscosity of about 0.01 to about 80 mm²/s at 40° C., it has very low viscosity near the body temperature of the wearer, and since it has a water holding percentage of about 0.01 to about 4.0 mass %, it exhibits constant affinity with menstrual blood and migrates together with menstrual blood into the absorbent body.

In addition, if the blood slipping agent has a hydrophobic portion composed of a hydrocarbon portion, and a hydrophilic portion composed of a hydrophilic group (a polar group, such as carbonyl, oxy, carboxyl or hydroxyl), a hydrophilic bond (a polar bond, such as a carbonyl bond, ester bond, carbonate bond or ether bond) or the like, the blood slipping agent will have an effect of facilitating sliding of menstrual blood.

The hydrophobic portion of the blood slipping agent repels the hydrophilic components in menstrual blood (such as blood plasma) while the hydrophilic portion of the blood slipping agent attracts the hydrophilic components in menstrual blood (such as blood plasma), and therefore menstrual blood will easily slide into the absorbent body.

In addition, since the blood slipping agent has a water holding percentage of about 0.01 to about 4.0 mass % and its affinity with the hydrophilic components (such as blood plasma) in menstrual blood is not excessively high, less of the menstrual blood remains on the top sheet.

Furthermore, since the blood slipping agent has a water holding percentage of about 0.01 to about 4.0 mass % and optionally an IOB of about 0.00 to about 0.60, its lipophilicity is high, and when the first embossed section and the optional third embossed section comprise a blood slipping agent, menstrual blood that has reached these areas is repelled into the excretory opening contact region.

[Blood Slipping Agent]

For the absorbent article of the present disclosure, the blood slipping agent has a kinematic viscosity of about 0.01 to about 80 mm²/s at 40° C., a water holding percentage of about 0.05 to about 4.0 mass %, and a weight-average molecular weight of less than about 1000.

The blood slipping agent has, at 40° C., a kinematic viscosity of about 0 to about 80 mm²/s, preferably a kinematic viscosity of about 1 to about 70 mm²/s, more preferably a kinematic viscosity of about 3 to about 60 mm²/s, even more preferably a kinematic viscosity of about 5 to about 50 mm²/s, and yet more preferably a kinematic viscosity of about 7 to about 45 mm²/s.

The kinematic viscosity tends to be higher with a) a larger molecular weight of the blood slipping agent, b) a higher percentage of polar bonds, such as carbonyl bonds (—CO—), ester bonds (—COO—), carbonate bonds (—OCOO—) and ether bonds (—O—), in groups, such as carbonyl groups (—CO—), oxy groups (—O—), carboxyl groups (—COOH), hydroxyl groups (—OH) and the like, and c) a larger IOB, explained below.

In order to have a kinematic viscosity of about 0 to about 80 mm²/s at 40° C., the melting point of the blood slipping agent is preferably 45° C. or less. This is because the kinematic viscosity will tend to be higher if the blood slipping agent contains crystals at 40° C.

As used herein, the “kinematic viscosity at 40° C.” may be referred to simply as “kinematic viscosity”.

A kinematic viscosity exceeding about 80 mm²/s will tend to result in high viscosity of the blood slipping agent, such that it will not as easily migrate into the absorbent body together with menstrual blood that has reached the skin contact surface of the top sheet.

The kinematic viscosity is measured according to JIS K 2283:2000, “5. Kinematic Viscosity Test Method”, using a Cannon-Fenske reverse-flow viscometer, at a testing temperature of 40° C.

The blood slipping agent has a water holding percentage of about 0.01 to about 4.0 mass %, preferably it has a water holding percentage of about 0.02 to about 3.5 mass %, more preferably it has a water holding percentage of about 0.03 to about 3.0 mass %, even more preferably it has a water holding percentage of about 0.04 to about 2.5 mass %, and yet more preferably it has a water holding percentage of about 0.05 to about 2.0 mass %.

As used herein, “water holding percentage” means the percentage of water that is held by a substance, and it is measured as follows.

(1) A test tube, a rubber stopper, the substance to be measured and deionized water are allowed to stand for a day and a night in a thermostatic chamber at 40° C.

(2) Into the 20 mL test tube in the thermostatic chamber there are charged 5.0 g of the substance to be measured and 5.0 g of deionized water.

(3) The mouth of the test tube is sealed with the rubber stopper in the thermostatic chamber, and it is rotated once and allowed to stand for 5 minutes.

(4) A 3.0 g portion of the layer of the substance to be measured (usually the upper layer) is sampled into a glass dish with a diameter of 90 mm (weight: W₀), in the thermostatic chamber.

(5) The dish is heated at 105° C. for 3 hours in an oven to evaporate off the moisture, and the weight of each dish is measured (weight: W₁).

(6) The water holding percentage is calculated by the following formula. Water holding percentage (%)=100×(W ₀ −W ₁)/3.0

The measurement is conducted three times, and the average value is recorded.

A low water holding percentage value will tend to lower the affinity between the blood slipping agent and menstrual blood, thus impeding its migration together with menstrual blood that has reached the skin contact surface of the top sheet. If the water holding percentage value increases, on the other hand, the affinity between menstrual blood and the blood modifying agent will become very high, similar to a surfactant, and absorbed menstrual blood will tend to remain on the skin contact surface of the top sheet, resulting in more red coloration of the skin contact surface of the top sheet.

When the water holding percentage value increases, affinity with menstrual blood also drastically increases, and menstrual blood that has reached the second embossed section will be less easily pushed back toward the excretory opening contact region.

Furthermore, when the water holding percentage value increases, affinity with menstrual blood also drastically increases, and when the first embossed section and the optional third embossed section contain a blood slipping agent, menstrual blood will be less easily repelled into the excretory opening contact region.

The water holding percentage value tends to be greater with a) a smaller molecular weight of the blood slipping agent, and b) a higher percentage of polar bonds, such as carbonyl bonds (—CO—), ester bonds (—COO—), carbonate bonds (—OCOO—) and ether bonds (—O—), in groups, such as carbonyl groups (—CO—), oxy groups (—O—), carboxyl groups (—COOH), hydroxyl groups (—OH) and the like. This is because the blood slipping agent has greater hydrophilicity. The water holding percentage will tend to have a larger value with a greater IOB, i.e with a higher inorganic value or with a lower organic value. This is because the blood slipping agent will have greater hydrophilicity.

The blood slipping agent has a weight-average molecular weight of less than about 1,000, and preferably a weight-average molecular weight of less than about 900. This is because, if the weight-average molecular weight is about 1,000 or higher, tack may result in the blood slipping agent itself, tending to create a feeling of unpleasantness for the wearer. If the weight-average molecular weight increases, the viscosity of the blood slipping agent will tend to increase, and it will therefore be difficult to lower the viscosity of the blood slipping agent by heating to a viscosity suitable for coating, and as a result, the blood slipping agent may need to be diluted with a solvent.

The blood slipping agent preferably has a weight-average molecular weight of about 100 or greater, and more preferably it has a weight-average molecular weight of about 200 or greater. This is because if the weight-average molecular weight is low, the vapor pressure of the blood slipping agent may be increased, gasification may occur during storage and the amount may be reduced, often leading to problems, such as odor of the blood slipping agent during wear.

In addition, as used herein, “weight-average molecular weight” includes the concept of a polydisperse compound (for example, a compound produced by stepwise polymerization, an ester formed from a plurality of fatty acids and a plurality of aliphatic monohydric alcohols), and a simple compound (for example, an ester formed from one fatty acid and one aliphatic monohydric alcohol), and in a system comprising N_(i) molecules with molecular weight M_(i) (i=1, or i=1, 2 . . . ), it refers to M_(w) determined by the following formula. M _(w) =ΣN _(i) M _(i) ² /ΣN _(i) M _(i)

As used herein, the weight-average molecular weights are the values measured by gel permeation chromatography (GPC), based on polystyrene.

The GPC measuring conditions may be the following, for example.

Device: Lachrom Elite high-speed liquid chromatogram by Hitachi High-Technologies Corp.

Columns: SHODEX KF-801, KF-803 and KF-804, by Showa Denko K.K.

Eluent: THF

Flow rate: 1.0 mL/min

Driving volume: 100 μL

Detection: RI (differential refractometer)

The weight-average molecular weights listed in the examples of the present specification were measured under the conditions described below.

The blood slipping agent can have an IOB of about 0.00 to about 0.60.

The IOB (Inorganic Organic Balance) is an indicator of the hydrophilic-lipophilic balance, and as used herein, it is the value calculated by the following formula by Oda et al.: IOB=inorganic value/organic value.

The inorganic value and the organic value are based on the organic paradigm described in “Organic compound predictions and organic paradigms” by Fujita A., Kagaku no Ryoiki (Journal of Japanese Chemistry), Vol. 11, No. 10 (1957) p. 719-725.

The organic values and inorganic values of major groups, according to Fujita, are summarized in Table 1 below.

TABLE 1 Inorganic Organic Group value value —COOH 150 0 —OH 100 0 —O—CO—O— 80 0 —CO— 65 0 —COOR 60 0 —O— 20 0 Triple bond 3 0 Double bond 2 0 CH₂ 0 20 iso-branch 0 −10 tert-branch 0 −20 Light metal (salt) ≧500 0 Heavy metal (salt), ≧400 0 amine, NH₃ salt

For example, in the case of an ester of tetradecanoic acid which has 14 carbon atoms and dodecyl alcohol which has 12 carbon atoms, the organic value is 520 (CH₂, 20×26) and the inorganic value is 60 (—COOR, 60×1), and therefore IOB=0.12.

The IOB of the blood slipping agent is preferably between about 0.00 and 0.60, more preferably between about 0.00 and 0.50, even more preferably between about 0.00 and 0.40 and most preferably between about 0.00 and 0.30. If the IOB is within this range, it will be easier to meet the aforementioned conditions for the water-holding capacity and kinematic viscosity.

When the IOB value increases, affinity with menstrual blood also drastically increases, and menstrual blood that has reached the embossed section will be less easily repelled into the excretory opening contact region.

In addition, when the IOB value increases, affinity with menstrual blood also drastically increases, and when the first embossed section and the optional third embossed section contain a blood slipping agent, menstrual blood will be less easily repelled into the excretory opening contact region.

The blood slipping agent preferably has a melting point of about 45° C. or less, and more preferably it has a melting point of about 40° C. or less. If the blood slipping agent has a melting point of about 45° C. or less, the blood slipping agent will more easily exhibit a kinematic viscosity in the aforementioned range.

As used herein, the term “melting point” refers to the peak top temperature for the endothermic peak during conversion from solid to liquid, upon measurement with a differential scanning calorimetry analyzer at a temperature-elevating rate of 10° C./min. The melting point may be measured using a Model DSC-60 DSC measuring apparatus by Shimadzu Corp., for example.

If the blood slipping agent has a melting point of about 45° C. or less, it may be either liquid or solid at room temperature (25° C.), or in other words, the melting point may be either about 25° C. or higher or below about 25° C., and for example, it may have a melting point of about −5° C. or about −20° C. The reason for a melting point of about 45° C. or less for the blood slipping agent will be explained below.

The blood slipping agent does not have a lower limit for the melting point thereof, but the vapor pressure is preferably low. The vapor pressure of the blood slipping agent is preferably about 0-200 Pa, more preferably about 0-100 Pa, even more preferably about 0-10 Pa, even more preferably about 0-1 Pa, and even more preferably about 0.0-0.1 Pa at 25° C. (1 atmosphere).

Considering that the absorbent article of the present disclosure is to be used in contact with the human body, the vapor pressure is preferably about 0-700 Pa, more preferably about 0-100 Pa, even more preferably about 0-10 Pa, even more preferably about 0-1 Pa, and even more preferably 0.0-0.1 Pa, at 40° C. (1 atmosphere). If the vapor pressure of the blood slipping agent is high, gasification may occur during storage and the amount may be reduced, often creating problems, such as odor during wear.

The melting point of the blood slipping agent may be selected depending on the weather or duration of wear. For example, in regions with a mean atmospheric temperature of about 10° C. or less, using a blood slipping agent with a melting point of about 10° C. or less helps the blood slipping agent function after excretion of menstrual blood, even if it has been cooled by the ambient temperature.

Also, when the absorbent article is to be used for a prolonged period of time, the melting point of the blood slipping agent is preferably at the high end of the range of about 45° C. or less. This is so that the blood slipping agent will not be easily affected by sweat or friction during wearing, and will not easily become biased even during prolonged wearing.

In the technical field, the skin contact surfaces of top sheets are coated with surfactants in order to alter the surface tension of menstrual blood and promote rapid absorption of menstrual blood. However, a top sheet coated with a surfactant has very high affinity for the hydrophilic components (blood plasma, etc.) in menstrual blood, and acts to attract them, tending to cause menstrual blood instead to remain on the top sheet. The blood slipping agent, unlike conventionally known surfactants, does not have excessively high affinity with menstrual blood and therefore does not cause residue of menstrual blood on the top sheet and allows rapid migration into the absorbent body.

Preferably, the blood slipping agent is selected from the group consisting of following items (i)-(iii), and any combination thereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen of the hydrocarbon moiety.

As used herein, “hydrocarbon” refers to a compound composed of carbon and hydrogen, and it may be a chain hydrocarbon, such as a paraffinic hydrocarbon (containing no double bond or triple bond, also referred to as alkane), an olefin-based hydrocarbon (containing one double bond, also referred to as alkene), an acetylene-based hydrocarbon (containing one triple bond, also referred to as alkyne), or a hydrocarbon comprising two or more bonds selected from the group consisting of double bonds and triple bonds, and cyclic hydrocarbon, such as aromatic hydrocarbons and alicyclic hydrocarbons.

Preferred as such hydrocarbons are chain hydrocarbons and alicyclic hydrocarbons, with chain hydrocarbons being more preferred, paraffinic hydrocarbons, olefin-based hydrocarbons and hydrocarbons with two or more double bonds (containing no triple bond) being more preferred, and paraffinic hydrocarbons being even more preferred.

Chain hydrocarbons include linear hydrocarbons and branched hydrocarbons.

When two or more oxy groups (—O—) are inserted in the compounds of (ii) and (iii) above, the oxy groups (—O—) are not adjacent each other. Thus, compounds (ii) and (iii) do not include compounds with continuous oxy groups (i.e., peroxides).

In the compounds of (iii), compounds in which at least one hydrogen on the hydrocarbon moiety is substituted with a hydroxyl group (—OH) are preferred over compounds in which at least one hydrogen on the hydrocarbon moiety is substituted with a carboxyl group (—COOH). This is because the carboxyl groups bond with metals and the like in menstrual blood, increasing the water holding percentage of the blood slipping agent, which may sometimes exceed the prescribed range. The same is true from the viewpoint of the IOB as well. As shown in Table 1, the carboxyl groups bond with metals and the like in menstrual blood, drastically increasing the inorganic value from 150 to 400 or greater, and therefore a blood slipping agent with carboxyl groups can increase the IOB value to more than about 0.60 during use.

More preferably, the blood slipping agent is selected from the group consisting of following items (i′)-(iii′), and any combination thereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii′-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen on the hydrocarbon moiety.

When 2 or more same or different bonds are inserted in the compound of (ii′) or (iii′), i.e., when 2 or more same or different bonds selected from the group consisting carbonyl bonds (—CO—), ester bonds (—COO—), carbonate bonds (—OCOO—) and ether bonds (—O—) are inserted, the bonds are not adjacent to each other, and at least one carbon atom lies between each of the bonds.

The blood slipping agent has more preferably about 1.8 or less carbonyl bonds (—CO—), about 2 or less ester bonds (—COO—), about 1.5 or less carbonate bonds (—OCOO—), about 6 or less ether bonds (—O—), about 0.8 or less carboxyl groups (—COOH) and/or about 1.2 or less hydroxyl groups (—OH), per 10 carbon atoms in the hydrocarbon moiety.

Even more preferably, the blood slipping agent is selected from the group consisting of following items (A)-(F), and any combination thereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (A2) a compound having a chain hydrocarbon moiety and 1 carboxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (B2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (C2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selected from the group consisting of ether bonds (—O—), carbonyl bonds (—CO—), ester bonds (—COO—) and carbonate bonds (—OCOO—) inserted between a C—C single bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl ether thereof; and

(F) a chain hydrocarbon.

The blood slipping agent in accordance with (A) to (F) will now be described in detail.

[(A) Ester of (A1) a Compound Having a Chain Hydrocarbon Moiety and 2-4 Hydroxyl Groups Substituting for Hydrogens on the Chain Hydrocarbon Moiety, and (A2) a Compound Having a Chain Hydrocarbon Moiety and 1 Carboxyl Group Substituting for a Hydrogen on the Chain Hydrocarbon Moiety]

In the (A) ester of (A1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (A2) a compound having a chain hydrocarbon moiety and 1 carboxyl group substituting for a hydrogen on the chain hydrocarbon moiety (hereunder also referred to as “compound (A)”), it is not necessary for all of the hydroxyl groups to be esterified so long as the kinematic viscosity, water holding percentage and weight-average molecular weight are within the aforementioned ranges.

Examples of (A1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety (hereunder also referred to as “compound (A1)”) include chain hydrocarbon tetraols, such as alkanetetraols, including pentaerythritol, chain hydrocarbon triols, such as alkanetriols, including glycerins, and chain hydrocarbon diols, such as alkanediols, including glycols.

Examples of (A2) a compound having a chain hydrocarbon moiety and 1 carboxyl group substituting for a hydrogen on the chain hydrocarbon moiety include compounds in which one hydrogen on the hydrocarbon is substituted with one carboxyl group (—COOH), such as fatty acids.

Examples for compound (A) include (a₁) an ester of a chain hydrocarbon tetraol and at least one fatty acid, (a₂) an ester of a chain hydrocarbon triol and at least one fatty acid, and (a₃) an ester of a chain hydrocarbon diol and at least one fatty acids.

[(a₁) Esters of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon tetraol and at least one fatty acid include tetraesters of pentaerythritol and fatty acids, represented by the following formula (1):

triesters of pentaerythritol and fatty acids, represented by the following formula (2):

diesters of pentaerythritol and fatty acids, represented by the following formula (3):

and monoesters of pentaerythritol and fatty acids, represented by the following formula (4).

In the formulas, R¹-R⁴ each represent a chain hydrocarbon.

The fatty acids consisting of the esters of pentaerythritol and fatty acids (R¹COOH, R²COOH, R³COOH, and R⁴COOH) are not particularly restricted so long as the pentaerythritol and fatty acid esters satisfy the conditions for the kinematic viscosity, water holding percentage and weight-average molecular weight, and for example, there may be mentioned saturated fatty acids, such as a C₂-C₃₀ saturated fatty acids, including acetic acid (C₂) (C₂ representing the number of carbons, corresponding to the number of carbons of each of R¹C, R²C, R³C or R⁴C, same hereunder), propanoic acid (C₃), butanoic acid (C₄) and isomers thereof, such as 2-methylpropanoic acid (C₄), pentanoic acid (C₅) and isomers thereof, such as 2-methylbutanoic acid (C₅) and 2,2-dimethylpropanoic acid (C₅), hexanoic acid (C₆), heptanoic acid (C₇), octanoic acid (C₈) and isomers thereof, such as 2-ethylhexanoic acid (C₈), nonanoic acid (C₉), decanoic acid (C₁₀), dodecanoic acid (C₁₂), tetradecanoic acid (C₁₄), hexadecanoic acid (C₁₆), heptadecanoic acid (C₁₇), octadecanoic acid (C₁₈), eicosanoic acid (C₂₀), docosanoic acid (C₂₂), tetracosanoic acid (C₂₄), hexacosanoic acid (C₂₆), octacosanoic acid (C₂₈), triacontanoic acid (C₃₀), as well as isomers thereof which are not described above.

The fatty acid may also be an unsaturated fatty acid. Examples of unsaturated fatty acids include C₃-C₂₀ unsaturated fatty acids, such as monounsaturated fatty acids including crotonic acid (C₄), myristoleic acid (C₁₄), palmitoleic acid (C₁₆), oleic acid (C₁₈), elaidic acid (C₁₈), vaccenic acid (C₁₈), gadoleic acid (C₂₀) and eicosenoic acid (C₂₀), di-unsaturated fatty acids including linolic acid (C₁₈) and eicosadienoic acid (C₂₀), tri-unsaturated fatty acids including linolenic acids, such as α-linolenic acid (C₁₈) and γ-linolenic acid (C₁₈), pinolenic acid (C₁₈), eleostearic acids, such as α-eleostearic acid (C₁₈) and β-eleostearic acid (C₁₈), Mead acid (C₂₀), dihomo-γ-linolenic acid (C₂₀) and eicosatrienoic acid (C₂₀), tetra-unsaturated fatty acids including stearidonic acid (C₂₀), arachidonic acid (C₂₀) and eicosatetraenoic acid (C₂₀), penta-unsaturated fatty acids including bosseopentaenoic acid (C₁₈) and eicosapentaenoic acid (C₂₀), and partial hydrogen adducts of the foregoing.

Considering the potential for degradation by oxidation and the like, the ester of pentaerythritol and a fatty acid is preferably an ester of pentaerythritol and a fatty acid, which is derived from a saturated fatty acid, i.e., an ester of pentaerythritol and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage, the ester of pentaerythritol and a fatty acid is preferably a diester, triester or tetraester, more preferably a triester or tetraester, and even more preferably a tetraester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a tetraester of pentaerythritol and a fatty acid, the total number of carbons of the fatty acid composing the tetraester of the pentaerythritol and fatty acid, i.e. the total number of carbons of the R¹C, R²C, R³C and R⁴C portions in formula (1), is preferably about 15 (the IOB is 0.60 when the total number of carbon atoms is 15).

Examples of tetraesters of pentaerythritol and fatty acids include tetraesters of pentaerythritol with hexanoic acid (C₆), heptanoic acid (C₇), octanoic acid (C₈), such as 2-ethylhexanoic acid (C₈), nonanoic acid (C9), decanoic acid (C₁₀) and/or dodecanoic acid (C₁₂).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a triester of pentaerythritol and a fatty acid, the total number of carbons of the fatty acid composing the triester of the pentaerythritol and fatty acid, i.e. the total number of carbons of the R¹C, R²C and R³C portions in formula (2), is preferably about 19 or greater (the IOB is 0.58 when the number of carbon atoms is 19).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a diester of pentaerythritol and a fatty acid, the total number of carbons of the fatty acid composing the diester of the pentaerythritol and fatty acid, i.e. the total number of carbons of the R¹C and R²C portion in formula (3), is preferably about 22 or greater (the IOB is 0.59 when the number of carbon atoms is 22).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a monoester of pentaerythritol and a fatty acid, the total number of carbons of the fatty acid composing the monoester of the pentaerythritol and fatty acid, i.e. the number of carbons of the R¹C portion in formula (4), is preferably about 25 or greater (the IOB is 0.60 when the number of carbon atoms is 25).

The effects of double bonds, triple bonds, iso-branches and tert-branches are not considered in this calculation of the IOB (same hereunder).

Commercial products which are esters of pentaerythritol and fatty acids include UNISTAR H-408BRS and H-2408BRS-22 (mixed product) (both products of NOF Corp.).

[(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon triol and at least one fatty acid include triesters of glycerin and fatty acids, represented by formula (5):

diesters of glycerin and fatty acids, represented by the following formula (6):

and monoesters of glycerin and fatty acids, represented by the following formula (7):

wherein R⁵-R⁷ each represent a chain hydrocarbon.

The fatty acid consisting of the ester of glycerin and a fatty acid (R⁵COOH, R⁶COOH and R⁷COOH) is not particularly restricted so long as the ester of glycerin and a fatty acid satisfies the conditions for the kinematic viscosity, water holding percentage and weight-average molecular weight, and for example, there may be mentioned the fatty acids mentioned for the “(a₁) Ester of a chain hydrocarbon tetraol and at least one fatty acid”, namely saturated fatty acids and unsaturated fatty acids, and in consideration of the potential for degradation by oxidation and the like, the ester is preferably a glycerin and fatty acid ester, which is derived from a saturated fatty acid, i.e., an ester of glycerin and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage and result in greater hydrophobicity, the ester of glycerin and a fatty acid is preferably a diester or triester, and more preferably a triester.

A triester of glycerin and a fatty acid is also known as a triglyceride, and examples include triesters of glycerin and octanoic acid (C₈), triesters of glycerin and decanoic acid (C₁₀), triesters of glycerin and dodecanoic acid (C₁₂), triesters of glycerin and 2 or more different fatty acids, and mixtures of the foregoing.

Examples of triesters of glycerin and 2 or more fatty acids include triesters of glycerin with octanoic acid (C₈) and decanoic acid (C₁₀), triesters of glycerin with octanoic acid (C₈), decanoic acid (C₁₀) and dodecanoic acid (C₁₂), and triesters of glycerin with octanoic acid (C₈), decanoic acid (C₁₀), dodecanoic acid (C12), tetradecanoic acid (C₁₄), hexadecanoic acid (C₁₆) and octadecanoic acid (C₁₈).

In order to obtain a melting point of about 45° C. or less, preferred triesters of glycerin and fatty acids are those with about 40 or less as the total number of carbons of the fatty acid consisting of the triester of glycerin and the fatty acid, i.e., the total number of carbons of the R⁵C, R⁶C and R⁷C sections in formula (5).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a triester of glycerin and a fatty acid, the total number of carbons of the fatty acid composing the triester of the glycerin and fatty acid, i.e. the total number of carbons of the R⁵C, R⁶C and R⁷C portions in formula (5), is preferably about 12 or greater (the IOB is 0.60 when the total number of carbon atoms is 12).

Triesters of glycerin and fatty acids, being aliphatic and therefore potential constituent components of the human body, are preferred from the viewpoint of safety.

Commercial products of triesters of glycerin and fatty acids include tri-coconut fatty acid glycerides, NA36, PANACET 800, PANACET 800B and PANACET 810S, and tri-C2L oil fatty acid glycerides and tri-CL oil fatty acid glycerides (all products of NOF Corp.).

A diester of glycerin and a fatty acid is also known as a diglyceride, and examples include diesters of glycerin and decanoic acid (C₁₀), diesters of glycerin and dodecanoic acid (C₁₂), diesters of glycerin and hexadecanoic acid (C₁₆), diesters of glycerin and 2 or more different fatty acids, and mixtures of the foregoing.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a diester of glycerin and a fatty acid, the total number of carbons of the fatty acid composing the diester of the glycerin and fatty acid, i.e. the total number of carbons of the R⁵C and R⁶C portions in formula (6), is preferably about 16 or greater (the IOB is 0.58 when the total number of carbon atoms is 16).

Monoesters of glycerin and fatty acids are also known as monoglycerides, and examples include glycerin and octadecanoic acid (C₁₈) monoester, and glycerin and docosanoic acid (C₂₂) monoester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a monoester of glycerin and a fatty acid, the total number of carbons of the fatty acid composing the monoester of the glycerin and fatty acid, i.e. the number of carbons of the R⁵C portion in formula (7), is preferably about 19 or greater (the IOB is 0.59 when the number of carbon atoms is 19).

[(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty Acid]

Examples of an ester of a chain hydrocarbon diol and at least one fatty acid include monoesters and diesters of fatty acids with C₂-C₆ chain hydrocarbon diols, such as C₂-C₆ glycols, including ethylene glycol, propylene glycol, butylene glycol, pentylene glycol and hexylene glycol.

Specifically, examples of an ester of a chain hydrocarbon diol and at least one fatty acid include diesters of C₂-C₆ glycols and fatty acids, represented by the following formula (8): R⁸COOC_(k)H_(2k)OCOR⁹  (8)

wherein k represents an integer of 2-6, and R⁸ and R⁹ each represent a chain hydrocarbon, and monoesters of C₂-C₆ glycols and fatty acids, represented by the following formula (9): R⁸COOC_(k)H_(2k)OH  (9)

wherein k represents an integer of 2-6, and R⁸ is a chain hydrocarbon.

The fatty acid to be esterified in an ester of a C₂-C₆ glycol and a fatty acid (corresponding to R⁸COOH and R⁹COOH in formula (8) and formula (9)) is not particularly restricted so long as the ester of the C₂-C₆ glycol and fatty acid satisfies the conditions for the kinematic viscosity, water holding percentage and weight-average molecular weight, and for example, there may be mentioned the fatty acids mentioned above for the “(a₁) Ester of a chain hydrocarbon tetraol and at least one fatty acid”, namely saturated fatty acids and unsaturated fatty acids, and in consideration of the potential for degradation by oxidation and the like, it is preferably a saturated fatty acid.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a diester of butylene glycol represented by formula (8) (k=4) and a fatty acid, the total number of carbons of the R⁸C and R⁹C portions is preferably about 6 or greater (the IOB is 0.60 when the total number of carbon atoms is 6).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a monoester of ethylene glycol represented by formula (9) (k=2) and a fatty acid, the number of carbons of the R⁸C portion is preferably about 12 or greater (the IOB is 0.57 when the number of carbon atoms is 12).

Considering the potential for degradation by oxidation and the like, the ester of the C₂-C₆ glycol and fatty acid is preferably a C₂-C₆ glycol and fatty acid ester derived from a saturated fatty acid, or in other words, an ester of a C₂-C₆ glycol and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage, the ester of the C₂-C₆ glycol and fatty acid is preferably a glycol and fatty acid ester derived from a glycol with a greater number of carbons, such as an ester of a glycol and a fatty acid derived from butylene glycol, pentylene glycol or hexylene glycol.

Also, from the viewpoint of lowering the water holding percentage, the ester of a C₂-C₆ glycol and fatty acid is preferably a diester.

Examples of commercial products of esters of C₂-C₆ glycols and fatty acids include COMPOL BL and COMPOL BS (both products of NOF Corp.).

[(B) Ether of (B1) a Compound Having a Chain Hydrocarbon Moiety and 2-4 Hydroxyl Groups Substituting for Hydrogens on the Chain Hydrocarbon Moiety and (B2) a Compound Having a Chain Hydrocarbon Moiety and 1 Hydroxyl Group Substituting for a Hydrogen on the Chain Hydrocarbon Moiety]

In the (B) ether of (B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety and (B2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety (hereunder also referred to as “compound (B)”), it is not necessary for all of the hydroxyl groups to be etherified so long as the kinematic viscosity, water holding percentage and weight-average molecular weight are within the aforementioned ranges.

Examples of (B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety (hereunder also referred to as “compound (B1)”) include those mentioned for “compound (A)” as compound (A1), such as pentaerythritol, glycerin and glycol.

Examples of (B2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety (hereunder also referred to as “compound (B2)”) include compounds wherein 1 hydrogen on the hydrocarbon is substituted with 1 hydroxyl group (—OH), such as aliphatic monohydric alcohols, including saturated aliphatic monohydric alcohols and unsaturated aliphatic monohydric alcohols.

Examples of saturated aliphatic monohydric alcohols include C₁-C₂₀ saturated aliphatic monohydric alcohols, such as methyl alcohol (C₁) (C₁ representing the number of carbon atoms, same hereunder), ethyl alcohol (C₂), propyl alcohol (C₃) and isomers thereof, including isopropyl alcohol (C₃), butyl alcohol (C₄) and isomers thereof, including sec-butyl alcohol (C₄) and tert-butyl alcohol (C₄), pentyl alcohol (C₅), hexyl alcohol (C₆), heptyl alcohol (C₇), octyl alcohol (C₈) and isomers thereof, including 2-ethylhexyl alcohol (C₈), nonyl alcohol (C₉), decyl alcohol (C₁₀), dodecyl alcohol (C₁₂), tetradecyl alcohol (C₁₄), hexadecyl alcohol (C₁₆), heptadecyl alcohol (C17), octadecyl alcohol (C₁₈) and eicosyl alcohol (C₂₀), as well as their isomers other than those mentioned.

Unsaturated aliphatic monohydric alcohols include those wherein 1 C—C single bond of a saturated aliphatic monohydric alcohol mentioned above is replaced with a C═C double bond, such as oleyl alcohol, and for example, such alcohols are commercially available by New Japan Chemical Co., Ltd. as the RIKACOL Series and UNJECOL Series.

Examples for compound (B) include (b₁) an ether of a chain hydrocarbon tetraol and at least one aliphatic monohydric alcohol, such as monoethers, diethers, triethers and tetraethers, preferably diethers, triethers and tetraethers, more preferably triethers and tetraethers and even more preferably tetraethers, (b₂) an ether of a chain hydrocarbon triol and at least one aliphatic monohydric alcohol, such as monoethers, diethers and triethers, preferably diethers and triethers and more preferably triethers, and (b₃) an ether of a chain hydrocarbon diol and at least one aliphatic monohydric alcohol, such as monoethers and diethers, and preferably diethers.

Examples of an ether of a chain hydrocarbon tetraol and at least one aliphatic monohydric alcohol include tetraethers, triethers, diethers and monoethers of pentaerythritol and aliphatic monohydric alcohols, represented by the following formulas (10)-(13):

wherein R¹⁰-R¹³ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon triol and at least one aliphatic monohydric alcohol include triethers, diethers and monoethers of glycerin and aliphatic monohydric alcohols, represented by the following formulas (14)-(16):

wherein R¹⁴-R¹⁶ each represent a chain hydrocarbon.

Examples of an ether of a chain hydrocarbon diol and at least one aliphatic monohydric alcohol include diethers of C₂-C₆ glycols and aliphatic monohydric alcohols, represented by the following formula (17): R¹⁷OC_(n)H_(2n)OR¹⁸  (17)

wherein n is an integer of 2-6, and R¹⁷ and R¹⁸ are each a chain hydrocarbon,

and monoethers of C₂-C₆ glycols and aliphatic monohydric alcohols, represented by the following formula (18): R¹⁷OC_(n)H_(2n)OH  (18)

wherein n is an integer of 2-6, and R¹⁷ is a chain hydrocarbon.

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a tetraether of pentaerythritol and an aliphatic monohydric alcohol, the total number of carbon atoms of the aliphatic monohydric alcohol composing the tetraether of pentaerythritol and the aliphatic monohydric alcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹, R¹² and R¹³ portions in formula (10), is preferably about 4 or greater (the IOB is 0.44 when the total number of carbon atoms is 4).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a triether of pentaerythritol and an aliphatic monohydric alcohol, the total number of carbon atoms of the aliphatic monohydric alcohol composing the triether of pentaerythritol and the aliphatic monohydric alcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹ and R¹² portions in formula (11), is preferably about 9 or greater (the IOB is 0.57 when the total number of carbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a diether of pentaerythritol and an aliphatic monohydric alcohol, the total number of carbon atoms of the aliphatic monohydric alcohol composing the diether of pentaerythritol and the aliphatic monohydric alcohol, i.e. the total number of carbon atoms of the R¹⁰ and R¹¹ portions in formula (12), is preferably about 15 or greater (the IOB is 0.60 when the total number of carbon atoms is 15).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a monoether of pentaerythritol and an aliphatic monohydric alcohol, the number of carbon atoms of the aliphatic monohydric alcohol composing the monoether of pentaerythritol and the aliphatic monohydric alcohol, i.e. the number of carbon atoms of the R¹⁰ portion in formula (13), is preferably about 22 or greater (the IOB is 0.59 when the number of carbon atoms is 22).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a triether of glycerin and an aliphatic monohydric alcohol, the total number of carbon atoms of the aliphatic monohydric alcohol composing the triether of glycerin and the aliphatic monohydric alcohol, i.e. the total number of carbon atoms of the R¹⁴, R¹⁵ and R¹⁶ portions in formula (14), is preferably about 3 or greater (the IOB is 0.50 when the total number of carbon atoms is 3).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a diether of glycerin and an aliphatic monohydric alcohol, the total number of carbon atoms of the aliphatic monohydric alcohol composing the diether of glycerin and the aliphatic monohydric alcohol, i.e. the total number of carbon atoms of the R¹⁴ and R¹⁵ portions in formula (15), is preferably about 9 or greater (the IOB is 0.58 when the total number of carbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60, in a monoether of glycerin and an aliphatic monohydric alcohol, the number of carbon atoms of the aliphatic monohydric alcohol composing the monoether of glycerin and the aliphatic monohydric alcohol, i.e. the number of carbon atoms of the R¹⁴ portion in formula (16), is preferably 16 or greater (the IOB is 0.58 when the number of carbon atoms is 16).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a diether of butylene glycol represented by formula (17) (n=4) and an aliphatic monohydric alcohol, the total number of carbon atoms of the R¹⁷ and R¹⁸ portions is preferably about 2 or greater (the IOB is 0.33 when the total number of carbon atoms is 2).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in a monoether of ethylene glycol represented by formula (18) (n=2) and an aliphatic monohydric alcohol, the number of carbon atoms of the R¹⁷ portion is preferably about 8 or greater (the IOB is 0.60 when the number of carbon atoms is 8).

Compound (B) may be produced by dehydrating condensation of compound (B1) and compound (B2) in the presence of an acid catalyst.

[(C) Ester of (C1) a Carboxylic Acid, Hydroxy Acid, Alkoxy Acid or Oxoacid Comprising a Chain Hydrocarbon Moiety and 2-4 Carboxyl Groups Substituting for Hydrogens on the Chain Hydrocarbon Moiety and (C2) a Compound Having a Chain Hydrocarbon Moiety and 1 Hydroxyl Group Substituting for a Hydrogen on the Chain Hydrocarbon Moiety]

In the (C) ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groups substituting for hydrogens on the chain hydrocarbon moiety and (C2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety (hereunder also referred to as “compound (C)”), it is not necessary for all of the carboxyl groups to be esterified so long as the kinematic viscosity, water holding percentage and weight-average molecular weight are within the aforementioned ranges.

Examples of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groups substituting for hydrogens on the chain hydrocarbon moiety (hereunder also referred to as “compound (C1)”) include chain hydrocarbon carboxylic acids with 2-4 carboxyl groups, such as chain hydrocarbon dicarboxylic acids including alkanedicarboxylic acids, such as ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioic acid and decanedioic acid, chain hydrocarbon tricarboxylic acids, including alkanetricarboxylic acids, such as propanetrioic acid, butanetrioic acid, pentanetrioic acid, hexanetrioic acid, heptanetrioic acid, octanetrioic acid, nonanetrioic acid and decanetrioic acid, and chain hydrocarbon tetracarboxylic acids, including alkanetetracarboxylic acids, such as butanetetraoic acid, pentanetetraoic acid, hexanetetraoic acid, heptanetetraoic acid, octanetetraoic acid, nonanetetraoic acid and decanetetraoic acid.

Compound (C1) includes chain hydrocarbon hydroxy acids with 2-4 carboxyl groups, such as malic acid, tartaric acid, citric acid and isocitric acid, chain hydrocarbon alkoxy acids with 2-4 carboxyl groups, such as O-acetylcitric acid, and chain hydrocarbon oxoacids with 2-4 carboxyl groups.

(C2) Compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety includes those mentioned for “compound (B)”, such as aliphatic monohydric alcohols.

Compound (C) may be (c₁) an ester, for example a monoester, diester, triester or tetraester, preferably a diester, triester or tetraester, more preferably a triester or tetraester and even more preferably a tetraester, of a chain hydrocarbon tetracarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and at least one aliphatic monohydric alcohol, (c₂) an ester, for example, a monoester, diester or triester, preferably a diester or triester and more preferably a triester, of a chain hydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and at least one aliphatic monohydric alcohol, or (c₃) an ester, for example, a monoester or diester, and preferably a diester, of a chain hydrocarbon dicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxyl groups, and at least one aliphatic monohydric alcohol.

Examples for compound (C) include dioctyl adipate, diisostearyl malate, tributyl citrate and tributyl O-acetylcitrate, of which commercially available products exist.

[(D) Compound Having a Chain Hydrocarbon Moiety and One Bond Selected from the Group Consisting of an Ether Bond (—O—), Carbonyl Bond (—CO—), Ester Bond (—COO—) and Carbonate Bond (—OCOO—) Inserted Between a C—C Single Bond of the Chain Hydrocarbon Moiety]

The (D) compound having a chain hydrocarbon moiety and one bond selected from the group consisting of an ether bond (—O—), carbonyl bond (—CO—), ester bond (—COO—) and carbonate bond (—OCOO—) inserted between a C—C single bond of the chain hydrocarbon moiety (hereunder also referred to as “compound (D)”) may be (d₁) an ether of an aliphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃) an ester of a fatty acid and an aliphatic monohydric alcohol, or (d₄) a dialkyl carbonate.

[(d₁) Ether of an Aliphatic Monohydric Alcohol and an Aliphatic Monohydric Alcohol]

Ethers of an aliphatic monohydric alcohol and an aliphatic monohydric alcohol include compounds having the following formula (19): R¹⁹OR²⁰  (19)

wherein R¹⁹ and R²⁰ each represent a chain hydrocarbon.

The aliphatic monohydric alcohol consisting of the ether (corresponding to R¹⁹OH and R²⁰OH in formula (19)) is not particularly restricted so long as the ether satisfies the conditions for the kinematic viscosity, water holding percentage and weight-average molecular weight, and for example, it may be one of the aliphatic monohydric alcohols mentioned for “compound (B)”.

[(d₂) Dialkyl Ketone]

The dialkyl ketone may be a compound of the following formula (20): R²¹COR²²  (20)

wherein R²¹ and R²² are each an alkyl group.

The dialkyl ketone may be a commercially available product, or it may be obtained by a known method, such as by oxidation of a secondary alcohol with chromic acid or the like.

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

Examples of esters of a fatty acid and an aliphatic monohydric alcohol include compounds having the following formula (21): R²³COOR²⁴  (21)

wherein R²³ and R²⁴ each represent a chain hydrocarbon.

Examples of fatty acids consisting of these esters (corresponding to R²³COOH in formula (21)) include the fatty acids mentioned for the “(a₁) an ester of a chain hydrocarbon tetraol and at least one fatty acids”, and specifically these include saturated fatty acids and unsaturated fatty acids, with saturated fatty acids being preferred in consideration of the potential for degradation by oxidation and the like. The aliphatic monohydric alcohol consisting of the ester (corresponding to R²⁴OH in formula (21)) may be one of the aliphatic monohydric alcohols mentioned for “compound (B)”.

Examples of esters of such fatty acids and aliphatic monohydric alcohols include esters of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂) and esters of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂), and examples of commercial products of esters of such fatty acids and aliphatic monohydric alcohols include ELECTOL WE20 and ELECTOL WE40 (both products of NOF Corp.).

[(d₄) Dialkyl Carbonate]

The dialkyl carbonate may be a compound of the following formula (22): R²⁵OC(═O)OR²⁶  (22)

wherein R²⁵ and R²⁶ are each an alkyl group.

The dialkyl carbonate may be a commercially available product, or it may be synthesized by reaction between phosgene and an alcohol, reaction between formic chloride and an alcohol or alcoholate, or reaction between silver carbonate and an alkyl iodide.

From the viewpoint of the water holding percentage and vapor pressure, the weight-average molecular weight is preferably about 100 or greater and more preferably about 200 or greater, for (d₁) an ether of an aliphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃) an ester of a fatty acid and an aliphatic monohydric alcohol, and (d₄) a dialkyl carbonate.

If the total number of carbon atoms is about 8 in a (d₂) dialkyl ketone, the melting point will be approximately −50° C. and the vapor pressure will be about 230 Pa at 20° C., in the case of 5-nonanone, for example.

[(E) Polyoxy C₃-C₆ Alkylene Glycol, or Alkyl Ester or Alkyl Ether Thereof]

The (E) polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl ether thereof (hereunder also referred to as “compound (E)”) may be (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkylene glycol and at least one fatty acid, or (e₃) an ether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphatic monohydric alcohol. These will now be explained.

[(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

Polyoxy C₃-C₆ alkylene glycols refer to i) one or more homopolymers having a unit selected from the group consisting of oxy C₃-C₆ alkylene units, such as oxypropylene unit, oxybutylene unit, oxypentylene unit and oxyhexylene unit and having hydroxyl groups at both ends, ii) one or more block copolymers having 2 or more units selected from oxy C₃-C₆ alkylene units described above and oxyhexylene unit and having hydroxyl groups at both ends, or iii) random copolymers having 2 or more units selected from oxy C₃-C₆ alkylene units described above and having hydroxyl groups at both ends.

The polyoxy C₃-C₆ alkylene glycol can be represented by the following formula (23): HO—(C_(m)H_(2m)O)_(n)—H  (23)

wherein m represents an integer of 3-6.

The present inventors have found that with polypropylene glycol (corresponding to a homopolymer of formula (23) where m=3), the condition for the water holding percentage is not satisfied when the weight-average molecular weight is less than about 1,000. Therefore, polypropylene glycol homopolymer is not included in the scope of the blood slipping agent described above, and propylene glycol is included in the (e₁) polyoxy C₃₋C₆ alkylene glycol only as a copolymer or random polymer with another glycol.

Incidentally, investigation by the present inventors suggests that with polyethylene glycol (corresponding to a homopolymer of formula (23) where m=2), the condition for the kinematic viscosity and water holding percentage cannot be satisfied when the weight-average molecular weight is less than about 1,000.

From the viewpoint of the IOB being about 0.00 to about 0.60, when formula (23) is polybutylene glycol (a homopolymer where m=4), for example, preferably n≧about 7 (when n=7, the IOB is 0.57).

Examples of commercial products of polyoxy C₃-C₆ alkylene glycols include UNIOL™ PB-500 and PB-700 (all products of NOF Corp.).

[(e₂) Ester of a Polyoxy C₃-C₆ Alkylene Glycol and at Least One Fatty Acid]

Examples of an ester of a polyoxy C₃-C₆ alkylene glycol and at least one fatty acids include the polyoxy C₃-C₆ alkylene glycols mentioned for “(e₁) Polyoxy C₃-C₆ alkylene glycol” in which one or both OH ends have been esterified with fatty acids, i.e. monoesters and diesters.

Examples of fatty acids to be esterified in the ester of a polyoxy C₃-C₆ alkylene glycol and at least one fatty acid include the fatty acids mentioned for the “(a₁) Ester of a chain hydrocarbon tetraol and at least one fatty acid”, and specifically these include saturated fatty acids and unsaturated fatty acids, with saturated fatty acids being preferred in consideration of the potential for degradation by oxidation and the like.

[(e₃) Ether of a Polyoxy C₃-C₆ Alkylene Glycol and at Least One Aliphatic Monohydric Alcohol]

Examples of an ether of a polyoxy C₃-C₆ alkylene glycols and at least one aliphatic monohydric alcohol include the polyoxy C₃-C₆ alkylene glycols mentioned for “(e₁) Polyoxy C₃-C₆ alkylene glycol” wherein one or both OH ends have been etherified by an aliphatic monohydric alcohol, i.e. monoethers and diethers.

In an ether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphatic monohydric alcohol, the aliphatic monohydric alcohol to be etherified may be an aliphatic monohydric alcohol among those mentioned for “compound (B)”.

[(F) Chain Hydrocarbon]

Examples of chain hydrocarbons include (f₁) chain alkanes, such as straight-chain alkanes and branched chain alkanes. Straight-chain alkanes with melting points of about 45° C. or less have up to about 22 carbon atoms, and at a vapor pressure of 1 atmosphere and about 0.01 Pa or less at 25° C., the number of carbon atoms is 13 or greater. Branched chain alkanes tend to have lower melting points than chain alkanes, given the same number of carbon atoms. Branched chain alkanes may therefore include those with 22 and more carbon atoms, even with melting points of below about 45° C.

Examples of commercially available hydrocarbon products include PARLEAM 6 (NOF Corp.).

The fibers composing such a woven fabric or nonwoven fabric as the liquid-permeable top sheet may be natural fibers or chemical fibers, with examples of natural fibers including cellulose, such as ground pulp and cotton, and examples of chemical fibers including regenerated cellulose, such as rayon and fibril rayon, semi-synthetic cellulose, such as acetate and triacetate, thermoplastic hydrophobic chemical fibers, and hydrophilicized thermoplastic hydrophobic chemical fibers.

Examples of thermoplastic hydrophobic chemical fibers include polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET) monofilaments, and fibers including PE and PP graft polymers.

Examples of nonwoven fabrics include air-through nonwoven fabrics, spunbond nonwoven fabrics, point bond nonwoven fabrics, spunlace nonwoven fabrics, needle punching nonwoven fabrics and meltblown nonwoven fabrics, as well as combinations thereof (such as SMS and the like).

The nonwoven fabric may also be a nonwoven fabric with a ridge-furrow structure comprising a plurality of ridges and a plurality of furrows, produced according to the method described in Japanese Unexamined Patent Publication No. 2008-2034.

Alternatively, the nonwoven fabric may be a nonwoven fabric with a ridge-furrow structure having a plurality of ridges and a plurality of furrows, produced according to the method described in Japanese Unexamined Patent Publication No. 2011-226010 or Japanese Unexamined Patent Publication No. 2011-226011. A nonwoven fabric with such a ridge-furrow structure can be formed by passing the nonwoven fabric to be treated through the gap between a pair of gear rolls with rotational axis lines that are perpendicular to the machine direction, and rotating while a plurality of teeth situated on the peripheral surfaces of each of the gear rolls are mutually engaged, and subjecting it to fluid treatment.

It is possible to form a top sheet with a plurality of ridges and a plurality of furrows extending in the lengthwise direction of the absorbent article, from a nonwoven fabric with such a ridge-furrow structure.

Liquid-impermeable back sheets include films comprising PE and PP, air-permeable resin films, air-permeable resin films bonded to spunbond or spunlace nonwoven fabrics, and multilayer nonwoven fabrics, such as SMS. In consideration of flexibility of the absorbent article, a low-density polyethylene (LDPE) film with a basis weight of about 15-30 g/m², for example, is preferred.

According to one embodiment of the absorbent article of the present disclosure, the absorbent article may comprise a second sheet between the liquid-permeable top sheet and the absorbent body. The second sheet may be any of the same examples as for the liquid-permeable top sheet.

The first example of the absorbent body is one having an absorbent core covered with a core wrap.

Examples of components for the absorbent core include hydrophilic fibers, including cellulose, such as ground pulp or cotton, regenerated cellulose, such as rayon or fibril rayon, semi-synthetic cellulose, such as acetate or triacetate, particulate polymers, filamentous polymers, thermoplastic hydrophobic chemical fibers, and hydrophilicized thermoplastic hydrophobic chemical fibers, as well as combinations of the foregoing. The component of the absorbent core may also be a super absorbent polymer, such as granules of a sodium acrylate copolymer or the like.

The core wrap is not particularly restricted so long as it is a substance that is liquid-permeable and with a barrier property that does not allow permeation of the polymer absorber, and it may be a woven fabric or nonwoven fabric, for example. The woven fabric or nonwoven fabric may be made of a natural fiber, chemical fiber, tissue, or the like.

A second example of the absorbent body is one formed from an absorbing sheet or polymer sheet, with a thickness of preferably about 0.3-5.0 mm. The absorbing sheet or polymer sheet may usually be used without any particular restrictions so long as it is one that can be used in an absorbent article, such as a sanitary napkin.

The first embossed section and second embossed section, and the optional third embossed section, may be formed by a method known in the art, and for example, the embossed section can be formed by using a pair of upper and lower embossing rolls, having a pattern formed on one of the rolls, for embossing of the top sheet and absorbent body (or the top sheet, second sheet and absorbent body) at a temperature below the melting point of the fibers and at a pressure of about 100 to about 1000 N/cm.

According to an embodiment of the absorbent article of the present disclosure, the top sheet within the excretory opening contact region and/or the second embossed section contain a blood slipping agent on the surface on the skin side, i.e. on the skin contact surface. According to another embodiment of the absorbent article of the present disclosure, the top sheet within the excretory opening contact region and/or the second embossed section contain a blood slipping agent on the skin contact surface and in the interior between the skin contact surface and the clothing side surface. According to yet another embodiment of the absorbent article of the present disclosure, the top sheet within the excretory opening contact region and/or the second embossed section contain a blood slipping agent over the entire thickness direction, i.e. on the skin contact surface, in the interior between the skin contact surface and the clothing side surface, and on the clothing side surface. If the blood slipping agent is present in the top sheet within the excretory opening contact region and/or the second embossed section interior and/or on the clothing side surface, menstrual blood present on the skin contact surface will rapidly migrate into the absorbent body.

According to one embodiment of the absorbent article of the present disclosure, the first embossed section and/or optional third embossed section contain the blood slipping agent on the skin contact surface. According to another embodiment of the absorbent article of the present disclosure, the first embossed section and/or the optional third embossed section comprise a blood slipping agent on the skin contact surface and in the interior between the skin contact surface and the clothing side surface. According to yet another embodiment of the absorbent article of the present disclosure, the first embossed section and/or the optional third embossed section comprise a blood slipping agent over the entire thickness direction, i.e. on the skin contact surface, in the interior between the skin contact surface and the clothing side surface, and on the clothing side surface. If a blood slipping agent is present inside the first embossed section and/or optionally the third embossed section and/or on the clothing side surface, menstrual blood that has reached that area will be easily repelled into the excretory opening contact region.

The blood slipping agent preferably does not obstruct the voids between the fibers of the nonwoven fabric or woven fabric composing the top sheet, and for example, the blood slipping agent may be attached as droplets or particulates on the surface of the nonwoven fabric or woven fabric fibers, or covering the surfaces of the fibers.

In order for the blood slipping agent to migrate together with the absorbed menstrual blood, and to repel menstrual blood, it preferably has a large surface area, and a blood slipping agent present as droplets or particulates preferably has a small droplet/particle size.

Preferably, the fibers composing the nonwoven fabric and woven fabric as the liquid-permeable top sheet are either coated on their surfaces with a hydrophilic agent, or the fiber starting material is mixed with a hydrophilic agent for hydrophilicizing treatment of the surfaces. This is because, if the fibers are hydrophilic, there will be lipophilic regions due to the blood slipping agent and hydrophilic regions due to the hydrophilic agent sparsely dispersed on the top sheet, which will facilitate migration of menstrual blood.

In an embodiment in which the domed section comprises a blood slipping agent, there are no particular restrictions on the method of coating the blood slipping agent, and coating to the intended area may be accomplished with heating as necessary, using a non-contact coater, such as for example, a spiral coater, curtain coater, spray coater or dip coater, or a contact coater or the like.

A non-contact coater is preferred from the viewpoint of uniformly dispersing the droplet or particulate blood slipping agent, and from the viewpoint of not causing damage in the top sheet. The blood slipping agent may be coated directly, if it is a liquid at room temperature, or it may be heated to lower the viscosity, and when it is a solid at room temperature, it may be heated to liquefaction and coated through a control seam hot melt adhesive (HMA) gun. By increasing the air pressure of the control seam HMA gun, it is possible to coat the blood slipping agent as fine particulates.

In an embodiment in which the domed section comprises a blood slipping agent, the blood slipping agent may be coated during production of the material for the top sheet and/or second sheet, such as the nonwoven fabric, or it may be coated in the manufacturing line for production of the absorbent article. In an embodiment in which the domed section comprises a blood slipping agent, from the viewpoint of minimizing equipment investment, the blood slipping agent is preferably coated in the manufacturing line for the absorbent article, and in order to prevent shedding of the blood slipping agent which may contaminate the line, the blood slipping agent is preferably coated during a step downstream from the manufacturing line, and specifically, immediately before encapsulation of the product in an individual package.

The blood slipping agent also has an effect as a lubricant. Thus, the blood slipping agent reduces friction between the fibers, and can improve flexibility across the entire nonwoven fabric or woven fabric.

According to a preferred embodiment of the absorbent article of the present disclosure, the absorbent article is one that is intended for absorption of menstrual blood, such as a sanitary napkin or panty liner.

An absorbent article of the present disclosure does not require components, such as emollients and immobilizing agents, unlike in an absorbent article containing a known skin care composition, lotion composition or the like, and the blood slipping agent alone may be applied to the top sheet.

EXAMPLES

The present disclosure will now be explained in fuller detail by examples, with the understanding that it is not meant to be limited to the examples.

Example 1 Evaluation of Rewetting Rate and Absorbent Body Migration Rate

A commercially available sanitary napkin was prepared, as shown in FIG. 1. The sanitary napkin was formed from a top sheet, formed of a hydrophilic agent-treated air-through nonwoven fabric (composite fiber composed of polyester and polyethylene terephthalate, basis weight: 35 g/m²), a second sheet, formed of an air-through nonwoven fabric (composite fiber composed of polyester and polyethylene terephthalate, basis weight: 30 g/m²), an absorbent body comprising pulp (basis weight: 150 to 450 g/m², increased at the center section), an acrylic super-absorbent polymer (basis weight: 15 g/m²) and tissue as a core wrap, a water-repellent agent-treated side sheet, and a back sheet composed of a polyethylene film.

The blood slipping agents used for testing are listed below.

[(a₁) Ester of a Chain Hydrocarbon Tetraols and at Least One Fatty Acid]

-   UNISTAR H-408BRS, product of NOF Corp.

Pentaerythritol tetra(2-ethylhexanoate), weight-average molecular weight: approximately 640

-   UNISTAR H-2408BRS-22, product of NOF Corp.

Mixture of pentaerythritol tetra(2-ethylhexanoate) and neopentylglycol di(2-ethylhexanoate) (58:42 as weight ratio), weight-average molecular weight: approximately 520

[(a₂) Ester of a Chain Hydrocarbon Triols and at Least One Fatty Acid]

-   Cetiol SB45DEO, Cognis Japan

Glycerin and fatty acid triester, with oleic acid or stearylic acid as the fatty acid.

-   SOY42, product of NOF Corp.

Glycerin and fatty acid triester with C₁₄ fatty acid:C₁₆ fatty acid:C₁₈ fatty acid:C₂₀ fatty acid (including both saturated fatty acids and unsaturated fatty acids) at a mass ratio of about 0.2:11:88:0.8, weight-average molecular weight: 880

-   Tri-C2L oil fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid:C₁₂ fatty acid at a mass ratio of about 37:7:56, weight-average molecular weight: approximately 570

-   Tri-CL oil fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₂ fatty acid at a mass ratio of about 44:56, weight-average molecular weight: approximately 570

-   PANACET 810s, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid at a mass ratio of about 85:15, weight-average molecular weight: approximately 480

-   PANACET 800, product of NOF Corp.

Glycerin and fatty acid triester with octanoic acid (C₈) as the entire fatty acid portion, weight-average molecular weight: approximately 470

-   PANACET 800B, product of NOF Corp.

Glycerin and fatty acid triester with 2-ethylhexanoic acid (C₈) as the entire fatty acid portion, weight-average molecular weight: approximately 470

-   NA36, product of NOF Corp.

Glycerin and fatty acid triester with C₁₆ fatty acid:C₁₈ fatty acid:C₂₀ fatty acid (including both saturated fatty acids and unsaturated fatty acids) at a mass ratio of about 5:92:3, weight-average molecular weight: approximately 880

-   Tri-coconut fatty acid glyceride, product of NOF Corp.

Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty acid:C₁₂ fatty acid:C₁₄ fatty acid:C₁₆ fatty acid (including both saturated fatty acids and unsaturated fatty acids) at a mass ratio of about 4:8:60:25:3, weight-average molecular weight: 670

-   Caprylic acid diglyceride, product of NOF Corp.

Glycerin and fatty acid diester with octanoic acid as the fatty acid, weight-average molecular weight: approximately 340

[(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty Acid]

-   UNISTAR H-208BRS, product of NOF Corp.

Neopentyl glycol di(2-ethylhexanoate), weight-average molecular weight: approximately 360

-   COMPOL BL, product of NOF Corp.

Dodecanoic acid (C₁₂) monoester of butylene glycol, weight-average molecular weight: approximately 270

-   COMPOL BS, product of NOF Corp.

Octadecanoic acid (C₁₈) monoester of butylene glycol, weight-average molecular weight: approximately 350

[(c₂) Ester of a Chain Hydrocarbon Tricarboxylic Acid, Hydroxy Acid, Alkoxy Acid or Oxoacid with 3 Carboxyl Groups, and at Least One Aliphatic Monohydric Alcohol]

-   Tributyl O-acetylcitrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 400

-   Tributyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 360

[(c₃) Ester of a Chain Hydrocarbon Dicarboxylic Acid, Hydroxy Acid, Alkoxy Acid or Oxoacid with 2 Carboxyl Groups, and at Least One Aliphatic Monohydric Alcohol]

-   Dioctyl adipate, product of Wako Pure Chemical Industries, Ltd.

Weight-average molecular weight: approximately 380

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

-   ELECTOL WE20, product of NOF Corp.

Ester of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂), weight-average molecular weight: approximately 360

-   ELECTOL WE40, product of NOF Corp.

Ester of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂), weight-average molecular weight: approximately 390

[(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

-   UNIOL PB500, product of NOF Corp.

Polybutylene glycol, weight-average molecular weight: approximately 500

-   UNIOL PB700, product of NOF Corp.

Polyoxybutylene polyoxypropylene glycol, weight-average molecular weight: approximately 700

[(f₁) Chain Alkane]

-   PARLEAM 6, product of NOF Corp.

Branched chain hydrocarbon, produced by copolymerization of liquid isoparaffin, isobutene and n-butene followed by hydrogen addition, polymerization degree: approximately 5-10, weight-average molecular weight: approximately 330

[Other Materials]

-   NA50, product of NOF Corp.

Glycerin and fatty acid triester obtained by addition of hydrogen to NA36 for reduced proportion of double bonds from unsaturated fatty acid starting material, weight-average molecular weight: approximately 880

-   (Caprylic acid/capric acid) monoglyceride, product of NOF Corp.

Glycerin and fatty acid monoester, with octanoic acid (C₈) and decanoic acid (C₁₀) at a mass ratio of about 85:15, weight-average molecular weight: approximately 220

-   Monomuls 90-L2 lauric acid monoglyceride, product of Cognis Japan -   Isopropyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

Weight-average molecular weight: approximately 230

-   Diisostearyl malate

Weight-average molecular weight: approximately 640

-   UNIOL PB1000R, product of NOF Corp.

Polybutylene glycol, weight-average molecular weight: approximately 1,000

-   UNIOL D-250, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 250

-   UNIOL D-400, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 400

-   UNIOL D-700, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 700

-   UNIOL D-1000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 1,000

-   UNIOL D-1200, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 1,160

-   UNIOL D-2000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 2,030

-   UNIOL D-3000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 3,000

-   UNIOL D-4000, product of NOF Corp.

Polypropylene glycol, weight-average molecular weight: approximately 4,000

-   PEG1500, product of NOF Corp.

Polyethylene glycol, weight-average molecular weight: approximately 1,500-1,600

-   WILBRITE cp9, product of NOF Corp.

Polybutylene glycol compound with OH groups at both ends esterified by hexadecanoic acid (C₁₆), weight-average molecular weight: approximately 1,150

-   UNILUBE MS-70K, product of NOF Corp.

Stearyl ether of polypropylene glycol, approximately 15 repeating units, weight-average molecular weight: approximately 1,140

-   NONION S-6, product of NOF Corp.

Polyoxyethylene monostearate, approximately 7 repeating units, weight-average molecular weight: approximately 880

-   UNILUBE 5TP-300KB

Polyoxyethylene polyoxypropylene pentaerythritol ether, produced by addition of 5 mol of ethylene oxide and 65 mol of propylene oxide to 1 mol of pentaerythritol, weight-average molecular weight: 4,130

-   WILBRITE s753, product of NOF Corp.

Polyoxyethylene polyoxypropylene polyoxybutylene glycerin, weight-average molecular weight: approximately 960

-   UNIOL TG-330, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 6 repeating units, weight-average molecular weight: approximately 330

-   UNIOL TG-1000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeating units, weight-average molecular weight: approximately 1,000

-   UNIOL TG-3000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeating units, weight-average molecular weight: approximately 3,000

-   UNIOL TG-4000, product of NOF Corp.

Glyceryl ether of polypropylene glycol, approximately 16 repeating units, weight-average molecular weight: approximately 4,000

-   UNILUBE DGP-700, product of NOF Corp.

Diglyceryl ether of polypropylene glycol, approximately 9 repeating units, weight-average molecular weight: approximately 700

-   UNIOX HC60, product of NOF Corp.

Polyoxyethylene hydrogenated castor oil, weight-average molecular weight: approximately 3,570

-   Vaseline, product of Cognis Japan

Petroleum-derived hydrocarbon, semi-solid

The kinematic viscosities, water holding percentages, weight-average molecular weights, IOBs and melting points of the samples are shown in Table 2.

For the melting point, “<45” indicates a melting point of below 45° C.

The excretory opening contact region of the top sheet of the sanitary napkin, and the second embossed section, were coated with the aforementioned blood slipping agent. Each blood slipping agent was used directly, when it was liquid at room temperature, or when the blood slipping agent was solid at room temperature it was heated to its melting point of +20° C., and then a control seam HMA gun was used for atomization of each blood slipping agent and coating onto the skin contact surface of the top sheet to a basis weight of about 5 g/m².

FIG. 3 is an electron micrograph of the skin contact surface of a top sheet in a sanitary napkin (No. 1-5) wherein the top sheet comprises tri-C2L oil fatty acid glycerides. As clearly seen in FIG. 3, the tri-C2L oil fatty acid glycerides are present on the fiber surfaces as fine particulates.

[Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40 mm×10 mm hole opened at the center) was placed on a top sheet comprising each blood slipping agent, and 3 g of horse EDTA blood at 37±1° C. (obtained by adding ethylenediaminetetraacetic acid (hereunder, “EDTA”) to horse blood to prevent coagulation) was dropped through the hole using a pipette (once), and after 1 minute, 3 g of horse EDTA blood at 37±1° C. was again added dropwise through the acrylic board hole with a pipette (twice).

After the second dropping of blood, the acrylic board was immediately removed and 10 sheets of filter paper (Qualitative filter paper No. 2, product of Advantech Toyo, Inc., 50 mm×35 mm) were placed on the location where the blood had been dropped, and then a weight was placed thereover to a pressure of 30 g/cm². After 1 minute, the filter paper was removed and the “rewetting rate” was calculated by the following formula. Rewetting rate (%)=100×(filter paper mass after test−initial filter paper mass)/6

In addition to the rewetting rate evaluation, the “absorbent body migration rate” was also measured as the time until migration of blood from the top sheet to the absorbent body after the second dropping of blood. The absorbent body migration rate is the time from introducing the blood onto the top sheet, until the redness of the blood could be seen on the surface and in the interior of the top sheet.

The results for the rewetting rate and absorbent body migration rate are shown below in Table 2.

The whiteness of the skin contact surface of the top sheet (TS) after the absorbent body migration rate test was visually evaluated on the following scale.

VG (Very Good): Virtually no redness of blood remaining, and no clear delineation between areas with and without blood.

G (Good): Slight redness of blood remaining, but difficult to delineate between areas with and without blood.

F (Fair): Slight redness of blood remaining, areas with blood discernible.

P (Poor): Redness of blood completely remaining.

The tack on the skin contact surface of the top sheet was also measured at 35° C., and evaluated on the following scale.

G: No tack

F: Slight tack

P: Tack

The results are summarized in Table 2 below.

TABLE 2 Kinematic Water Absorbent viscosity holding Weight- Melting body (mm²/s, percentage average pt. Rewetting migration TS No. Blood lubricity imparter 40° C.) (mass %) mol. wt. IOB (° C.) rate (%) rate (sec) whiteness Tack 1-1 H-408BRS  45 0.7 640 0.13 <−5 1.2  3 VG G 1-2 H-2408BRS-22  22 0.8 520 0.18 <−5 2.0  3 VG G 1-3 Cetiol SB45DEO 0.16 44 7.0  6 VG 1-4 SOY42 880 0.16 43 5.8  8 VG G 1-5 Tri-C2L oil fatty acid  20 <1.0 570 0.27 37 0.3  3 VG G glycerides 1-6 Tri-CL oil fatty acid  15 <1.0 570 0.28 38 1.7  3 VG G glycerides 1-7 PANACET 810s   9 0.3 480 0.32 −5 2.8  3 VG G 1-8 PANACET 800  15 0.5 470 0.33 −5 0.3  3 VG G 1-9 PANACET 800B  20 <1.0 470 0.33 −5 2.0  3 VG G 1-10 NA36  40 <1.0 880 0.16 37 3.9  5 VG G 1-11 Tri-coconut oil fatty  25 <1.0 670 0.28 30 4.3  5 VG G acid glycerides 1-12 Caprylic acid  25 2.7 340 0.58 <45 4.2  9 G G diglyceride 1-13 UNISTAR H-208BRS   8 0.7 360 0.24 <−5 2.0  5 VG G 1-14 COMPOL BL  10 1.6 270 0.50 2 2.0  5 G G 1-15 COMPOL BS  35 0.3 350 0.36 37 7.9  9 G G 1-16 Tributyl O-acetylcitrate  15 0.9 400 0.60 <45 6.2  8 VG G 1-17 Tributyl citrate  12 0.6 360 0.78 <45 3.0  6 G G 1-18 Dioctyl adipate   7 0.4 380 0.27 <45 1.7  6 VG G 1-19 ELECTOL WE20  10 0.3 360 0.13 29 1.8  5 VG G 1-20 ELECTOL WE40  15 0.5 390 0.12 37 1.8  4 VG G 1-21 UNIOL PB500  40 3.6 500 0.44 <45 4.5  4 G G 1-22 UNIOL PB700  50 2.3 700 0.49 −5 2.8  5 G G 1-23 PARLEAM 6   5 0.06 330 0.00 −5 6.0  8 VG G 1-24 NA50      80<< —* 880 0.18 52 15.5 60 P G 1-25 (Caprylic acid/Capric  70 4.0<< 220 1.15 <45 4.0  4 P G acid) monoglyceride 1-26 90-L2 Lauric acid      80<< 4.0<< <1,000 0.87 58 6.2  7 P G monoglyceride 1-27 Isopropyl citrate  120 4.0<< 230 1.56 <45 12.2  5 G F 1-28 Diisostearyl malate  450 4.0<< 640 0.28 <45 5.5  8 F F 1-29 UNIOL PB1000R  70 5.5 1000 0.40 <45 4.0  4 G F 1-30 UNIOL D-250  20 4.0<< 250 <45 — — P G 1-31 UNIOL D-400  30 4.0<< 400 0.76 <45 8.7 40 P G 1-32 UNIOL D-700  50 34.6 700 0.58 <45 7.5 — F G 1-33 UNIOL D-1000  70 26.7 1,000 0.51 <45 6.8 15 F F 1-34 UNIOL D-1200  90 16.2 1,160 0.48 <45 0.5 11 F F 1-35 UNIOL D-2000 160 2,030 <45 — — F P 1-36 UNIOL D-3000 0.6 3,000 0.39 <45 1.7 10 F P 1-37 UNIOL D-4000  450 0.5 4,000 0.38 <45 1.0  7 G P 1-38 PEG1500  120 4.0<< 1,500-1,600 0.78 40 11.0 38 P P 1-39 WILBRITE CP9  120 0.6 1,150 0.21 35 1.4  3 G P 1-40 UNILUBE MS-70K  50 2.8 1,140 0.30 <−10 6.7  3 G F 1-41 NONION S-6  65 4.0<< 880 0.44 37 8.4  7 P G 1-42 UNILUBE 5TP-300KB  310 3.9 4,130 0.39 <45 2.0  6 G P 1-43 WILBRITE s753  120 27.3 960 0.67 −5 9.3  9 F F 1-44 UNIOL TG-330  30 330 1.27 <45 — — — G 1-45 UNIOL TG-1000  100 21.2 1,000 0.61 <45 14.2  7 G G 1-46 UNIOL TG-3000  230 4.3 3,000 0.42 <45 0.8  6 G P 1-47 UNIOL TG-4000  300 2.4 4,000 0.40 <45 2.0  6 G P 1-48 UNILUBE DGP-700  200 4.0<< 700 0.91 <0 8.0 10 F F 1-49 UNIOX HC60 1150 3,570 0.46 33 14.6 46 P P 1-50 Vaseline      80<< 0.0 <1,000 0.00 55 9.7 10 F P 1-51 None — — — — — 22.7   60< P G *Viscosity too high for measurement.

In the absence of a blood slipping agent, the rewetting rate was 22.7% and the absorbent body migration rate was greater than 60 seconds, but the glycerin and fatty acid triesters all produced rewetting rates of 7.0% or less and absorbent body migration rates of no longer than 8 seconds, and therefore significantly improved the absorption performance.

Similarly, it was found that the absorption performance is greatly improved with a blood slipping agent having a kinematic viscosity of about 0.01 to 80 mm²/s at 40° C., a water holding percentage of about 0.01 to about 4.0 mass %, and a weight-average molecular weight of less than about 1000.

Next, several volunteer subjects were asked to wear sanitary napkins Nos. 1-1 to 1-51, and the obtained responses indicated that with the sanitary napkins comprising blood slipping agent Nos. 1-1 to 1-23, the top sheets had no sticky feel and the top sheets were smooth, even after absorption of menstrual blood.

Also, with sanitary napkins that comprised blood slipping agents No. 1-1 to 1-23, and especially No. 1-11, 13, 16, 18 to 20 and 23, the responses indicated that the excretory opening contact region of the top sheet after absorption of menstrual blood was not easily reddened by blood, and that minimal unpleasantness was experienced. Also, with No. 1-1 to 1-23, and especially No. 1-11, 13, 16, 18 to 20 and 23, the responses indicated that the excretory opening contact region of the top sheet was not easily colored red with menstrual blood, but that since the second embossed section was reddened after absorption of a large amount of menstrual blood by the absorbent body, it was easy to visually confirm the time for replacement. The responses also indicated resistance to leakage even with prolonged wear.

The following experiment was also conducted in order to confirm the function of the blood slipping agent.

Example 2 Surface Residue Rate of Menstrual Blood on Top Sheet with Ridge-Furrow Structure

The surface residue rate of menstrual blood on a top sheet with a ridge-furrow structure was evaluated.

There were prepared a top sheet, formed of a hydrophilic agent-treated air-through nonwoven fabric (composite fiber composed of polyester and polyethylene terephthalate, basis weight: 35 g/m²), a second sheet, formed of an air-through nonwoven fabric (composite fiber composed of polyester and polyethylene terephthalate, basis weight: 30 g/m²), an absorbent body comprising pulp (basis weight: 150 to 450 g/m², increased at the center section), an acrylic super-absorbent polymer (basis weight: 15 g/m²) and tissue as a core wrap, a water-repellent agent-treated side sheet, and a back sheet composed of a polyethylene film.

The top sheet was a top sheet produced by the method described in Japanese Unexamined Patent Publication No. 2008-2034, having a ridge-furrow structure, with a ridge thickness of approximately 1.5 mm and a furrow thickness of approximately 0.4 mm, the pitch of the ridge-furrow structure (ridge width+furrow width) was approximately 4 mm, and open holes were formed in the furrows at an open area of approximately 15%.

UNISTAR H-408BRS (product of NOF Corp., tetraester of pentaerythritol and fatty acid) was selected as the blood slipping agent, and it was coated onto the skin contact surface (ridge-furrow side) of the top sheet from a control seam HMA gun at room temperature, to a basis weight of 5.0 g/m². With an electron microscope it was confirmed that the H-408BRS was adhering onto the fiber surfaces as fine particulates.

A back sheet, an absorbent body, a second sheet, and a top sheet with the ridge-furrow side facing upward, were stacked in that order to form sanitary napkin No. 2-1.

Sanitary napkins No. 2-2 to No. 2-40 were produced, changing the blood slipping agent from UNISTAR H-408BRS to the ones listed in Table 3. Each blood slipping agent was used directly, when it was liquid at room temperature, or when the blood slipping agent was solid at room temperature it was heated to its melting point of +20° C., and then a control seam HMA gun was used for atomization of the blood slipping agent and coating onto the skin contact surface of the top sheet to a basis weight of about 5 g/m².

The blood slipping agent was coated onto essentially the entire skin contact surface of the top sheet, and on both the ridges and furrows.

[Test Methods]

After measuring the weight W₂ of the top sheet (the weight of the top sheet before the test), an acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40 mm×10 mm hole opened at the center) was placed on the top sheet, at the center section in the lengthwise direction and widthwise direction of the absorbent article, and 4.0 g of horse EDTA blood at 37±1° C. (obtained by adding ethylenediaminetetraacetic acid (hereunder, “EDTA”) to horse blood to prevent coagulation) was dropped through the hole using a pipette.

After dropping the horse EDTA blood, the acrylic board was immediately removed, the top sheet was taken off, the weight W₃ (weight of top sheet after the test) was measured and the “surface residue rate (mass %)” was calculated by the following formula. Surface residue rate (mass %)=100×(W ₃ −W ₂)/4.0

The results are summarized in Table 3 below.

TABLE 3 Surface residue No. Blood slipping agent rate (mass %) 2-1 H-408BRS 0.8 2-2 H-2408BRS-22 0.8 2-3 PANACET 810s 0.8 2-4 PANACET 800 1.8 2-5 Caprylic acid diglyceride 1.0 2-6 UNISTAR H-208BRS 0.5 2-7 COMPOL BL 1.3 2-8 COMPOL BS 2.5 2-9 Tributyl O-acetylcitrate 0.5 2-10 Tributyl citrate 1.8 2-11 Dioctyl adipate 1.5 2-12 ELECTOL WE20 0.5 2-13 ELECTOL WE40 2.3 2-14 UNIOL PB500 2.5 2-15 UNIOL PB700 1.3 2-16 PARLEAM 6 2.0 2-17 NA50 4.3 2-18 (Caprylic acid/capric acid) monoglyceride 5.0 2-19 90-L2 Lauric acid monoglyceride 5.0 2-20 Isopropyl citrate 4.8 2-21 Diisostearyl malate 3.3 2-22 UNIOL PB1000R 2.5 2-23 UNIOL D-250 3.8 2-24 UNIOL D-400 4.8 2-25 UNIOL D-700 4.8 2-26 UNIOL D-1000 3.8 2-27 UNIOL D-1200 3.0 2-28 UNIOL D-3000 3.0 2-29 UNIOL D-4000 2.5 2-30 PEG1500 5.5 2-31 WILBRITE CP9 6.8 2-32 UNILUBE MS-70K 1.5 2-33 UNILUBE 5TP-300KB 2.0 2-34 WILBRITE s753 3.5 2-35 UNIOL TG-1000 3.5 2-36 UNIOL TG-3000 1.0 2-37 UNIOL TG-4000 2.0 2-38 UNILUBE DGP-700 3.5 2-39 Vaseline 4.0 2-40 None 7.5

With sanitary napkin No. 2-40, which had no blood slipping agent, the surface residue rate was 7.5 mass %, but with sanitary napkins No. 2-1 to No. 2-16 wherein the kinematic viscosity and water holding percentage were within the prescribed ranges, the surface residue rate was 2.5 mass % or lower.

With sanitary napkins No. 2-1 to No. 2-16, it was observed that the horse EDTA blood that was dropped onto the ridges of the top sheet slipped down from the ridges into the furrows, and was rapidly absorbed from the furrows into the absorbent body. However, with sanitary napkin No. 2-40 which had no blood slipping agent, the dropped horse EDTA blood did not slip down into the furrows but slowly dripped down into the furrows, most of it remaining on the ridges of the top sheet. Also, with the absorbent articles with high water holding percentage, as with No. 2-25, for example, the horse EDTA blood that was dropped onto the ridges of the top sheet did not slip down into the furrows but slowly dripped while partially remaining on the top sheet, and a portion thereof remained on the ridges.

Example 3 Viscosity of Blood Containing Blood Slipping Agent

The viscosity of the blood slipping agent-containing blood was measured using a Rheometric Expansion System ARES (Rheometric Scientific, Inc.). After adding 2 mass % of PANACET 810s to horse defibrinated blood, the mixture was gently agitated to form a sample, the sample was placed on a 50 mm-diameter parallel plate, with a gap of 100 μm, and the viscosity was measured at 37±0.5° C. The sample was not subjected to a uniform shear rate due to the parallel plate, but the average shear rate indicated by the device was 10 s⁻¹.

The viscosity of the horse defibrinated blood containing 2 mass % PANACET 810s was 5.9 mPa·s, while the viscosity of the horse defibrinated blood containing no blood slipping agent was 50.4 mPa·s. Thus, the horse defibrinated blood containing 2 mass % PANACET 810s clearly had an approximately 90% lower viscosity than the blood containing no blood slipping agent.

It is known that blood contains components, such as blood cells and has a thixotropic nature, and the blood slipping agent of the present disclosure has an effect of lowering the viscosity of blood, such as menstrual blood in the low viscosity range. Lowering the blood viscosity allows absorbed menstrual blood to more easily migrate rapidly from the top sheet to the absorbent body.

Example 4 Photomicrograph of Blood Slipping Agent-Containing Menstrual Blood

Menstrual blood was sampled from healthy volunteers onto thin plastic wrap, and PANACET 810s dispersed in a 10-fold mass of phosphate-buffered saline was added to a portion thereof to a PANACET 810s concentration of 1 mass %. The menstrual blood was dropped onto a slide glass, a cover glass was placed thereover, and the state of the erythrocytes was observed with an optical microscope. A photomicrograph of menstrual blood containing no blood slipping agent is shown in FIG. 4(a), and a photomicrograph of menstrual blood containing PANACET 810s is shown in FIG. 4(b).

FIG. 4(a) shows that the erythrocytes formed aggregates, including a rouleaux structure, in the menstrual blood containing no blood slipping agent, while FIG. 4(b) shows that the erythrocytes were stably dispersed in the menstrual blood containing PANACET 810s. This suggests that the blood slipping agent has the function of stabilizing erythrocytes in menstrual blood.

Example 5 Surface Tension of Blood Containing Blood Slipping Agent

The surface tension of blood containing a blood slipping agent was measured by the pendant drop method, using a Drop Master500 contact angle meter by Kyowa Interface Science Co., Ltd. The surface tension was measured after adding a prescribed amount of blood slipping agent to sheep defibrinated blood, and thoroughly shaking.

The measurement was accomplished automatically with a device, and the surface tension γ was determined by the following formula (see FIG. 5). γ=g×ρ×(de)²×1/H

g: Gravitational constant

1/H: Correction factor determined from ds/de

ρ: Density

de: Maximum diameter

ds: Diameter at location of increase by de from dropping edge

The density ρ was measured at the temperatures listed in Table 4, according to JIS K 2249-1995, “Density test methods and density/mass/volume conversion tables”, “5. Vibrating density test method”.

The measurement was accomplished using a DA-505 by Kyoto Electronics Co., Ltd.

The results are shown in Table 4 below.

TABLE 4 Blood slipping agent Measuring Surface Amount temperature tension No. Type (mass %) (° C.) (mN/m) 4-1 — — 35 62.1 4-2 PANACET 0.01 35 61.5 4-3 810s 0.05 35 58.2 4-4 0.10 35 51.2 4-5 ELECTOL 0.10 35 58.8 WE20 4-6 PARLEAM 0.10 35 57.5 6 4-7 — — 50 56.3 4-8 WILBRITE 0.10 50 49.1 cp9

Based on Table 4 it is seen that the blood slipping agent has an effect of lowering the surface tension of blood.

Lowering the surface tension of blood allows absorbed blood to rapidly migrate from the top sheet to the absorbent body, without being retained between the top sheet fibers.

The present disclosure relates to the following J1 to J15.

[J1]

An absorbent article comprising a liquid-permeable top sheet, formed from a nonwoven fabric or woven fabric, a liquid-impermeable back sheet, and an absorbent body between the top sheet and the back sheet,

wherein the absorbent article has, in a region overlapping the absorbent body in a thickness direction, an excretory opening contact region that contacts with an excretory opening of a wearer, a first embossed section which is continuously or discontinuously disposed and which surrounds the excretory opening contact region, a fringe region on an outer side of the first embossed section, and a second embossed section disposed in the fringe region, located on an outer side of the excretory opening contact region in a lengthwise direction,

the first embossed section and second embossed section are formed by embossing a layer comprising the top sheet and the absorbent body, and

the top sheet within the excretory opening contact region and the second embossed section each comprise a blood slipping agent that has a kinematic viscosity of 0.01 to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0 mass % and a weight-average molecular weight of less than 1000.

[J2]

The absorbent article according to J1, wherein the blood slipping agent further has an IOB of 0.00-0.60.

[J3]

The absorbent article according to J1 or J2, wherein the second embossed section is disposed and curved so as to surround the edges of the excretory opening contact region in the lengthwise direction.

[J4]

The absorbent article according to any one of J1 to J3, wherein the top sheet has a region that does not comprise the blood slipping agent, between the excretory opening contact region and the second embossed section.

[J5]

The absorbent article according to any one of J1 to J4, wherein the first embossed section further comprises the blood slipping agent.

[J6]

The absorbent article according to any one of J1 to J5, wherein the first embossed section is discontinuously disposed and surrounds the excretory opening contact region, and third embossed section is further disposed on the outer side of the first embossed section.

[J7]

The absorbent article according to J6, wherein the third embossed section is disposed on the outer sides of discontinuous sections of the first embossed section.

[J8]

The absorbent article according to J6 or J7, wherein the third embossed section comprises the blood slipping agent.

[J9]

The absorbent article according to any one of J1 to J8, wherein the absorbent article further comprises a second sheet between the top sheet and the absorbent body, and the first embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.

[J10]

The absorbent article according to J9, wherein the second embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.

[J11]

The absorbent article according to any one of J1 to J10, wherein the blood slipping agent is selected from the group consisting of following items (i)-(iii), and any combination thereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen of the hydrocarbon moiety;

with the proviso that when 2 or more oxy groups are inserted in the compound of (ii) or (iii), the oxy groups are not adjacent.

[J12]

The absorbent article according to any one of J1 to J11, wherein the blood slipping agent is selected from the group consisting of following items (i′)-(iii′), and any combination thereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii′-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen on the hydrocarbon moiety;

with the proviso that when 2 or more same or different bonds are inserted in a compound of (ii′) or (iii′), the bonds are not adjacent.

[J13]

The absorbent article according to any one of J1 to J12, wherein the blood slipping agent is selected from the group consisting of following items (A)-(F), and any combination thereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (A2) a compound having a chain hydrocarbon moiety and 1 carboxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (B2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (C2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selected from the group consisting of ether bonds (—O—), carbonyl bonds (—CO—), ester bonds (—COO—) and carbonate bonds (—OCOO—) inserted between a C—C single bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl ether thereof; and

(F) a chain hydrocarbon.

[J14]

The absorbent article according to any one of J1 to J13, wherein the blood slipping agent is selected from the group consisting of (a₁) an ester of a chain hydrocarbon tetraol and at least one fatty acid, (a₂) an ester of a chain hydrocarbon triol and at least one fatty acid, (a₃) an ester of a chain hydrocarbon diol and at least one fatty acid, (b₁) an ether of a chain hydrocarbon tetraol and at least one aliphatic monohydric alcohol, (b₂) an ether of a chain hydrocarbon triol and at least one aliphatic monohydric alcohol, (b₃) an ether of a chain hydrocarbon diol and at least one aliphatic monohydric alcohol, (c₁) an ester of a chain hydrocarbon tetracarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and at least one aliphatic monohydric alcohol, (c₂) an ester of a chain hydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and at least one aliphatic monohydric alcohol, (c₃) an ester of a chain hydrocarbon dicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxyl groups, and at least one aliphatic monohydric alcohol, (d₁) an ether of an aliphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃) an ester of a fatty acid and an aliphatic monohydric alcohol, (d₄) a dialkyl carbonate, (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkylene glycols and at least one fatty acid, (e₃) an ether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphatic monohydric alcohol, and (f₁) a chain alkane, and any combination thereof.

REFERENCES SIGNS LIST

-   1 Sanitary napkin -   2 Top sheet -   3 Absorbent body -   4 Excretory opening contact region -   5 First embossed section -   6 Fringe region -   7 Second embossed section -   8 Third embossed section -   9 Non-agent-containing region -   10 Discontinuous section 

The invention claimed is:
 1. An absorbent article comprising a liquid-permeable top sheet, formed from a nonwoven fabric or woven fabric, a liquid-impermeable back sheet, and an absorbent body between the top sheet and the back sheet, wherein the absorbent article has, in a region overlapping the absorbent body in a thickness direction, an excretory opening contact region that contacts with an excretory opening of a wearer, a first embossed section which is continuously or discontinuously disposed and which surrounds the excretory opening contact region, a fringe region on an outer side of the first embossed section, and a second embossed section disposed in the fringe region, located on an outer side of the excretory opening contact region in a lengthwise direction, the first embossed section and second embossed section are formed by embossing a layer comprising the top sheet and the absorbent body, and the top sheet within the excretory opening contact region and the second embossed section each comprise a blood slipping agent that has a kinematic viscosity of 0.01 to 80 mm²/s at 40° C., a water holding percentage of 0.01 to 4.0 mass % and a weight-average molecular weight of less than
 1000. 2. The absorbent article according to claim 1, wherein the blood slipping agent further has an IOB of 0.00-0.60.
 3. The absorbent article according to claim 1, wherein the second embossed section is disposed and curved so as to surround the edges of the excretory opening contact region in the lengthwise direction.
 4. The absorbent article according to claim 1, wherein the top sheet has a region that does not comprise the blood slipping agent, between the excretory opening contact region and the second embossed section.
 5. The absorbent article according to claim 1, wherein the first embossed section further comprises the blood slipping agent.
 6. The absorbent article according to claim 1, wherein the first embossed section is discontinuously disposed and surrounds the excretory opening contact region, and a third embossed section is further disposed on the outer side of the first embossed section.
 7. The absorbent article according to claim 6, wherein the third embossed section is disposed on the outer sides of discontinuous sections of the first embossed section.
 8. The absorbent article according to claim 6, wherein the third embossed section comprises the blood slipping agent.
 9. The absorbent article according to claim 1, wherein the absorbent article further comprises a second sheet between the top sheet and the absorbent body, and the first embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.
 10. The absorbent article according to claim 9, wherein the second embossed section is formed by embossing the layer comprising the top sheet, second sheet and absorbent body.
 11. The absorbent article according to claim 1, wherein the blood slipping agent is selected from the group consisting of following items (i)-(iii), and any combination thereof: (i) a hydrocarbon; (ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and (iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one or more, same or different groups selected from the group consisting of carbonyl group (—CO—) and oxy group (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen of the hydrocarbon moiety; with the proviso that when 2 or more oxy groups are inserted in the compound of (ii) or (iii), the oxy groups are not adjacent.
 12. The absorbent article according to claim 1, wherein the blood slipping agent is selected from the group consisting of following items (i′)-(iii′), and any combination thereof: (i′) a hydrocarbon; (ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety; and (iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one or more, same or different bonds selected from the group consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), and ether bond (—O—) inserted between a C—C single bond of the hydrocarbon moiety, and (iii′-3) one or more, same or different groups selected from the group consisting of carboxyl group (—COOH) and hydroxyl group (—OH) substituting for a hydrogen on the hydrocarbon moiety; with the proviso that when 2 or more same or different bonds are inserted in a compound of (ii′) or (iii′), the bonds are not adjacent.
 13. The absorbent article according to claim 1, wherein the blood slipping agent is selected from the group consisting of following items (A)-(F), and any combination thereof: (A) an ester of (A1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (A2) a compound having a chain hydrocarbon moiety and 1 carboxyl group substituting for a hydrogen on the chain hydrocarbon moiety; (B) an ether of (B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (B2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety; (C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groups substituting for hydrogens on the chain hydrocarbon moiety, and (C2) a compound having a chain hydrocarbon moiety and 1 hydroxyl group substituting for a hydrogen on the chain hydrocarbon moiety; (D) a compound having a chain hydrocarbon moiety and one bond selected from the group consisting of ether bonds (—O—), carbonyl bonds (—CO—), ester bonds (—COO—) and carbonate bonds (—OCOO—) inserted between a C—C single bond of the chain hydrocarbon moiety; (E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl ether thereof; and (F) a chain hydrocarbon.
 14. The absorbent article according to claim 1, wherein the blood slipping agent is selected from the group consisting of (a₁) an ester of a chain hydrocarbon tetraol and at least one fatty acid, (a₂) an ester of a chain hydrocarbon triol and at least one fatty acid, (a₃) an ester of a chain hydrocarbon diol and at least one fatty acid, (b₁) an ether of a chain hydrocarbon tetraol and at least one aliphatic monohydric alcohol, (b₂) an ether of a chain hydrocarbon triol and at least one aliphatic monohydric alcohol, (b₃) an ether of a chain hydrocarbon diol and at least one aliphatic monohydric alcohol, (c₁) an ester of a chain hydrocarbon tetracarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and at least one aliphatic monohydric alcohol, (c₂) an ester of a chain hydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and at least one aliphatic monohydric alcohol, (c₃) an ester of a chain hydrocarbon dicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxyl groups, and at least one aliphatic monohydric alcohol, (d₁) an ether of an aliphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃) an ester of a fatty acid and an aliphatic monohydric alcohol, (d₄) a dialkyl carbonate, (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkylene glycols and at least one fatty acid, (e₃) an ether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphatic monohydric alcohol, and (f₁) a chain alkane, and any combination thereof. 